Search for "radical-mediated" in Full Text gives 49 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22
Graphical Abstract
Figure 1: Influence of the metal center M (Fe, Ru, Os) on the position of the MLCT and MC (metal-centered) ab...
Scheme 1: Red-light-mediated ring-closing metathesis through activation of a ruthenium catalyst by an osmium ...
Scheme 2: Photocatalyzed polymerization of dicylopentadiene mediated with red or blue light.
Figure 2: Comparison between [Ru(bpy)3]2+ and [Os(tpy)2]2+ in a photocatalyzed trifluoromethylation reaction:...
Scheme 3: Red-light photocatalyzed C–N cross-coupling reaction by T. Rovis et al. (SET = single-electron tran...
Figure 3: Red-light-mediated aryl oxidative addition with a bismuthinidene complex.
Scheme 4: Red-light-mediated reduction of aryl derivatives by O. S. Wenger et al. (PC = photocatalyst, anh = ...
Scheme 5: Red-light-mediated aryl halides reduction with an isoelectronic chromium complex (TDAE = tetrakis(d...
Scheme 6: Red-light-photocatalyzed trifluoromethylation of styrene derivatives with Umemoto’s reagent and a p...
Scheme 7: Red-light-mediated energy transfer for the cross-dehydrogenative coupling of N-phenyltetrahydroisoq...
Scheme 8: Red-light-mediated oxidative cyanation of tertiary amines with a phthalocyanin zinc complex.
Scheme 9: Formation of dialins and tetralins via a red-light-photocatalyzed reductive decarboxylation mediate...
Scheme 10: Oxidation of β-citronellol (28) via energy transfer mediated by a red-light activable silicon phtha...
Scheme 11: Formation of alcohol derivatives 32 from boron compounds 31 using chlorophyll (chl) as a red-light-...
Scheme 12: Red-light-driven reductive dehalogenation of α-halo ketones mediated by a thiaporphyrin photocataly...
Figure 4: Photoinduced electron transfer-reversible addition-fragmentation chain transfer polymerization medi...
Figure 5: Recent examples of red-light-mediated photocatalytic reactions with traditional organic dyes.
Figure 6: Squaraine photocatalysts used by Goddard et al. and aza-Henry reaction with squaraine-based photoca...
Figure 7: Reactions described by Goddard et al. involving 40 as the photocatalyst.
Figure 8: Various structures of squaraine derivatives used to initiate photopolymerizations.
Figure 9: Naturally occurring cyanins.
Figure 10: Influence of the structure on the photophysical properties of a cyanin dye.
Figure 11: NIR-light-mediated aza-Henry reaction photocatalyzed by 46.
Scheme 13: Photocatalyzed arylboronic acids oxidation by 46.
Figure 12: Cyanin structures synthetized and characterized by Goddard et al. (redox potentials given against s...
Figure 13: N,N′-Di-n-propyl-1,13-dimethoxyquinacridinium (55) with its redox potentials at its ground state an...
Scheme 14: Dual catalyzed C(sp2)–H arylation of 57 using DMQA 55 as the red-light-absorbing photocatalyst.
Scheme 15: Red-light-mediated aerobic oxidation of arylboronic acids 59 into phenols 60 via the use of DMQA as...
Figure 14: Red-light-photocatalyzed reactions proposed by Gianetti et al. using DMQA as the photocatalyst.
Scheme 16: Simultaneous release of NO and production of superoxide (O2•−) and their combination yielding the p...
Figure 15: Palladium porphyrin complex as the photoredox catalyst and the NO releasing substrate are linked in...
Scheme 17: Uncaging of compound 69 which is a microtubule depolymerizing agent using near IR irradiation. The ...
Scheme 18: Photochemical uncaging of drugs protected with a phenylboronic acid derivative using near IR irradi...
Scheme 19: Photoredox catalytical generation of aminyl radicals with near IR irradiation for the transfer of b...
Scheme 20: Photoredox catalytical fluoroalkylation of tryptophan moieties.
Figure 16: Simultaneous absorption of two photons of infrared light of low energy enables electronic excitatio...
Scheme 21: Uncaging Ca2+ ions using two-photon excitation with near infrared light.
Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9
Graphical Abstract
Figure 1: General mechanisms of traditional and radical-mediated cross-coupling reactions.
Figure 2: Types of electrocatalysis (using anodic oxidation).
Figure 3: Recent developments and features of electrochemical copper catalysis.
Figure 4: Scheme and proposed mechanism for Cu-catalyzed alkynylation and annulation of benzamide.
Figure 5: Scheme and proposed mechanism for Cu-catalyzed asymmetric C–H alkynylation.
Figure 6: Scheme for Cu/TEMPO-catalyzed C–H alkenylation of THIQs.
Figure 7: Scheme and proposed mechanism for Cu-catalyzed electrophotochemical enantioselective cyanation of b...
Figure 8: Scheme and proposed mechanism for Cu-catalyzed electrophotochemical asymmetric heteroarylcyanation ...
Figure 9: Scheme and proposed mechanism for Cu-catalyzed enantioselective regiodivergent cross-dehydrogenativ...
Figure 10: Scheme and proposed mechanism for Cu/Ni-catalyzed stereodivergent homocoupling of benzoxazolyl acet...
Figure 11: Scheme and proposed mechanism for Cu-catalyzed electrochemical amination.
Figure 12: Scheme and proposed mechanism for Cu-catalyzed electrochemical azidation of N-arylenamines and annu...
Figure 13: Scheme and proposed mechanism for Cu-catalyzed electrochemical halogenation.
Figure 14: Scheme and proposed mechanism for Cu-catalyzed asymmetric cyanophosphinoylation of vinylarenes.
Figure 15: Scheme and proposed mechanism for Cu/Co dual-catalyzed asymmetric hydrocyanation of alkenes.
Figure 16: Scheme and proposed mechanism for Cu-catalyzed electrochemical diazidation of olefins.
Figure 17: Scheme and proposed mechanism for Cu-catalyzed electrochemical azidocyanation of alkenes.
Figure 18: Scheme and proposed mechanism for Cu-catalyzed electrophotochemical asymmetric decarboxylative cyan...
Figure 19: Scheme and proposed mechanism for electrocatalytic Chan–Lam coupling.
Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249
Graphical Abstract
Scheme 1: Organic peroxide initiators in polymer chemistry.
Scheme 2: Synthesis of organic peroxides.
Scheme 3: Richness of radical cascades with species formed from hydroperoxides in redox conditions.
Scheme 4: Co-catalyzed allylic peroxidation of alkenes 1 and 3 by TBHP.
Scheme 5: Allylic peroxidation of alkenes 6 by Pd(II)TBHP.
Scheme 6: Cu(I)-catalyzed allylic peroxidation.
Scheme 7: Enantioselective peroxidation of alkenes 10 with TBHP in the presence of copper(I) compounds.
Scheme 8: Oxidation of α-pinene (12) by the Cu(I)/TBHP system.
Scheme 9: Introduction of the tert-butylperoxy fragment into the α-position of cyclic ketones 15 and 17.
Scheme 10: α-Peroxidation of β-dicarbonyl compounds 19 using the Cu(II)/TBHP system.
Scheme 11: Co-catalyzed peroxidation of cyclic compounds 21 with TBHP.
Scheme 12: Co-, Mn- and Fe-catalyzed peroxidation of 2-oxoindoles 23, barbituric acids 25, and 4-hydroxycoumar...
Scheme 13: Cu-catalyzed and metal-free peroxidation of barbituric acid derivatives 31 and 3,4-dihydro-1,4-benz...
Scheme 14: Electrochemical peroxidation of 1,3-dicarbonyl compounds 35.
Scheme 15: Peroxidation of β-dicarbonyl compounds, cyanoacetic esters and malonic esters 37 by the TBAI/TBHP s...
Scheme 16: Cu-catalyzed peroxidation of malonodinitriles and cyanoacetic esters 39 with TBHP.
Scheme 17: Mn-catalyzed remote peroxidation via trifluromethylation of double bond.
Scheme 18: Cu-catalyzed remote peroxidation via trifluromethylthiolation of double bond.
Scheme 19: Fe-, Mn-, and Ru-catalyzed peroxidation of alkylaromatics 45, 47, 49, and 51 with TBHP.
Scheme 20: Cu-catalyzed peroxidation of diphenylacetonitrile (53) with TBHP.
Scheme 21: Cu-catalyzed peroxidation of benzyl cyanides 60 with TBHP.
Scheme 22: Synthesis of tert-butylperoxy esters 63 from benzyl alcohols 62 using the TBAI/TBHP system.
Scheme 23: Enantioselective peroxidation of 2-phenylbutane (64) with TBHP and chiral Cu(I) complex.
Scheme 24: Photochemical synthesis of peroxides 67 from carboxylic acids 66.
Scheme 25: Photochemical peroxidation of benzylic C(sp3)–H.
Scheme 26: Cu- and Ru-catalyzed peroxidation of alkylamines with TBHP.
Scheme 27: Peroxidation of amides 76 with the TBAI/TBHP system.
Scheme 28: Fe-catalyzed functionalization of ethers 78 with TBHP.
Scheme 29: Synthesis of 4-(tert-butylperoxy)-5-phenyloxazol-2(3H)-ones 82 from benzyl alcohols 80 and isocyana...
Scheme 30: Fe- and Co-catalyzed peroxidation of alkanes with TBHP.
Scheme 31: Rh-catalyzed tert-butylperoxy dienone synthesis with TBHP.
Scheme 32: Rh- and Cu-catalyzed phenolic oxidation with TBHP.
Scheme 33: Metal-free peroxidation of phenols 94.
Scheme 34: Cu-catalyzed alkylation–peroxidation of acrylonitrile.
Scheme 35: Cu-catalyzed cycloalkylation–peroxidation of coumarins 99.
Scheme 36: Metal-free cycloalkylation–peroxidation of coumarins 102.
Scheme 37: Difunctionalization of indene 104 with tert-butylperoxy and alkyl groups.
Scheme 38: Acid-catalyzed radical addition of ketones (108, 111) and TBHP to alkenes 107 and acrylates 110.
Scheme 39: Cu-catalyzed alkylation–peroxidation of alkenes 113 with TBHP and diazo compounds 114.
Scheme 40: Cobalt(II)-catalyzed addition of TBHP and 1,3-dicarbonyl compound 116 to alkenes 117.
Scheme 41: Cu(0)- or Co(II)-catalyzed addition of TBHP and alcohols 120 to alkenes 119.
Scheme 42: Fe-catalyzed functionalization of allenes 122 with TBHP.
Scheme 43: Fe-catalyzed alkylation–peroxidation of alkenes 125 and 127.
Scheme 44: Fe- and Co-catalyzed alkylation–peroxidation of alkenes 130, 133 and 134 with TBHP and aldehydes as...
Scheme 45: Carbonylation–peroxidation of alkenes 137, 140, 143 with hydroperoxides and aldehydes.
Scheme 46: Carbamoylation–peroxidation of alkenes 146 with formamides and TBHP.
Scheme 47: TBAB-catalyzed carbonylation–peroxidation of alkenes.
Scheme 48: VOCl2-catalyzed carbonylation–peroxidation of alkenes 152.
Scheme 49: Acylation–peroxidation of alkenes 155 with aldehydes 156 and TBHP using photocatalysis.
Scheme 50: Cu-catalyzed peroxidation of styrenes 158.
Scheme 51: Fe-catalyzed acylation-peroxidation of alkenes 161 with carbazates 160 and TBHP.
Scheme 52: Difunctionalization of alkenes 163, 166 with TBHP and (per)fluoroalkyl halides.
Scheme 53: Difunctionalization of alkenes 169 and 172 with hydroperoxides and sodium (per)fluoromethyl sulfina...
Scheme 54: Trifluoromethylation–peroxidation of styrenes 175 using MOF Cu3(BTC)2 as a catalyst.
Scheme 55: Difunctionalization of alkenes 178 with tert-butylperoxy and dihalomethyl fragments.
Scheme 56: Difunctionalization of alkenes 180 with the tert-butylperoxy and dihalomethyl moieties.
Scheme 57: The nitration–peroxidation of alkenes 182 with t-BuONO and TBHP.
Scheme 58: Azidation–peroxidation of alkenes 184 with TMSN3 and TBHP.
Scheme 59: Co-catalyzed bisperoxidation of butadiene 186.
Scheme 60: Bisperoxidation of styrene (189) and acrylonitrile (192) with TBHP by Minisci.
Scheme 61: Mn-catalyzed synthesis of bis(tert-butyl)peroxides 195 from styrenes 194.
Scheme 62: Bisperoxidation of arylidene-9H-fluorenes 196 and 3-arylidene-2-oxoindoles 198 with TBHP under Mn-c...
Scheme 63: Synthesis of bisperoxides from styrenes 200 and 203 using the Ru and Rh catalysis.
Scheme 64: Iodine-catalyzed bisperoxidation of styrenes 206.
Scheme 65: Synthesis of di-tert-butylperoxyoxoindoles 210 from acrylic acid anilides 209 using a Pd(II)/TBHP o...
Scheme 66: Pinolation/peroxidation of styrenes 211 catalyzed by Cu(I).
Scheme 67: TBAI-catalyzed acyloxylation–peroxidation of alkenes 214 with carboxylic acids and TBHP.
Scheme 68: Difunctionalization of alkenes 217 with TBHP and water or alcohols.
Scheme 69: TBAI-catalyzed hydroxyperoxidation of 1,3-dienes 220.
Scheme 70: Hydroxyperoxidation of 1,3-dienes 220.
Scheme 71: Iodination/peroxidation of alkenes 223 with I2 and hydroperoxides.
Scheme 72: The reactions of cyclic enol ethers 226 and 228 with I2/ROOH system.
Scheme 73: Synthesis of 1-(tert-butylperoxy)-2-iodoethanes 231.
Scheme 74: Synthesis of 1-iodo-2-(tert-butylperoxy)ethanes 233.
Scheme 75: Cu-catalyzed phosphorylation–peroxidation of alkenes 234.
Scheme 76: Co-catalyzed phosphorylation–peroxidation of alkenes 237.
Scheme 77: Ag-catalyzed sulfonylation–peroxidation of alkenes 241.
Scheme 78: Co-catalyzed sulfonylation–peroxidation of alkenes 244.
Scheme 79: Synthesis of α/β-peroxysulfides 248 and 249 from styrenes 247.
Scheme 80: Cu-catalyzed trifluoromethylthiolation–peroxidation of alkenes 250 and allenes 252.
Scheme 81: Photocatalytic sulfonyl peroxidation of alkenes 254 via deamination of N-sulfonyl ketimines 255.
Scheme 82: Photoredox-catalyzed 1,4-peroxidation–sulfonylation of enynones 257.
Scheme 83: Cu-catalyzed silylperoxidation of α,β-unsaturated compounds 260 and enynes 261.
Scheme 84: Fe-catalyzed silyl peroxidation of alkenes.
Scheme 85: Cu-catalyzed germyl peroxidation of alkenes 267.
Scheme 86: TBAI-catalyzed intramolecular cyclization of diazo compounds 269 with further peroxidation.
Scheme 87: Co-catalyzed three-component coupling of benzamides 271, diazo compounds 272 and TBHP.
Scheme 88: Co-catalyzed esterification-peroxidation of diazo compounds 274 with TBHP and carboxylic acids 275.
Scheme 89: Cu-catalyzed alkylation–peroxidation of α-carbonylimines 277 or ketones 280.
Scheme 90: Mn-catalyzed ring-opening peroxidation of cyclobutanols 282 with TBHP.
Scheme 91: Peroxycyclization of tryptamines 284 with TBHP.
Scheme 92: Radical cyclization–peroxidation of homotryptamines 287.
Scheme 93: Iodine-catalyzed oxidative coupling of indoles 288, cyanoacetic esters and TBHP.
Scheme 94: Summary of metal-catalyzed peroxidation processes.
Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243
Graphical Abstract
Figure 1: Various structures of iodonium salts.
Scheme 1: Αrylation of α-fluoroacetoacetamides 5 to α-aryl-α-fluoroacetoacetamides 7 and α-fluoroacetamides 8...
Scheme 2: Proposed mechanism for the arylation of α-fluoroacetoacetamides 5 to α-aryl-α-fluoroacetoacetamides ...
Scheme 3: α-Arylation of α-nitro- and α-cyano derivatives of α-fluoroacetamides 9 employing unsymmetrical DAI...
Scheme 4: Synthesis of α,α-difluoroketones 13 by reacting α,α-difluoro-β-keto acid esters 11 with aryl(TMP)io...
Scheme 5: Coupling reaction of arynes generated by iodonium salts 6 and arynophiles 14 for the synthesis of t...
Scheme 6: Metal-free arylation of quinoxalines 17 and quinoxalinones 19 with DAISs 16.
Scheme 7: Transition-metal-free, C–C cross-coupling of 2-naphthols 21 to 1-arylnapthalen-2-ols 22 employing d...
Scheme 8: Arylation of vinyl pinacol boronates 23 to trans-arylvinylboronates 24 in presence of hypervalent i...
Scheme 9: Light-induced selective arylation at C2 of quinoline N-oxides 25 and pyridine N-oxides 28 in the pr...
Scheme 10: Plaussible mechanism for the light-induced selective arylation of N-heterobiaryls.
Scheme 11: Photoinduced arylation of heterocycles 31 with the help of diaryliodonium salts 16 activated throug...
Scheme 12: Arylation of MBH acetates 33 with DIPEA and DAIRs 16.
Scheme 13: Aryl sulfonylation of MBH acetates 33 with DABSO and diphenyliodonium triflates 16.
Scheme 14: Synthesis of oxindoles 37 from N-arylacrylamides 36 and diaryliodonium salts 26.
Scheme 15: Mechanically induced N-arylation of amines 38 using diaryliodonium salts 16.
Scheme 16: o-Fluorinated diaryliodonium salts 40-mediated diarylation of amines 38.
Scheme 17: Proposed mechanism for the diarylation of amines 38 using o-fluorinated diaryliodonium salts 40.
Scheme 18: Ring-opening difunctionalization of aliphatic cyclic amines 41.
Scheme 19: N-Arylation of amino acid esters 44 using hypervalent iodonium salts 45.
Scheme 20: Regioselective N-arylation of triazole derivatives 47 by hypervalent iodonium salts 48.
Scheme 21: Regioselective N-arylation of tetrazole derivatives 50 by hypervalent iodonium salt 51.
Scheme 22: Selective arylation at nitrogen and oxygen of pyridin-2-ones 53 by iodonium salts 16 depending on t...
Scheme 23: N-Arylation using oxygen-bridged acyclic diaryliodonium salt 56.
Scheme 24: The successive C(sp2)–C(sp2)/O–C(sp2) bond formation of naphthols 58.
Scheme 25: Synthesis of diarylethers 62 via in situ generation of hypervalent iodine salts.
Scheme 26: O-Arylated galactosides 64 by reacting protected galactosides 63 with hypervalent iodine salts 16 i...
Scheme 27: Esterification of naproxen methyl ester 65 via formation and reaction of naproxen-containing diaryl...
Scheme 28: Etherification and esterification products 72 through gemfibrozil methyl ester-derived diaryliodoni...
Scheme 29: Synthesis of iodine containing meta-substituted biaryl ethers 74 by reacting phenols 61 and cyclic ...
Scheme 30: Plausible mechanism for the synthesis of meta-functionalized biaryl ethers 74.
Scheme 31: Intramolecular aryl migration of trifluoromethane sulfonate-substituted diaryliodonium salts 75.
Scheme 32: Synthesis of diaryl ethers 80 via site-selective aryl migration.
Scheme 33: Synthesis of O-arylated N-alkoxybenzamides 83 using aryl(trimethoxyphenyl)iodonium salts 82.
Scheme 34: Synthesis of aryl sulfides 85 from thiols 84 using diaryliodonium salts 16 in basic conditions.
Scheme 35: Base-promoted synthesis of diarylsulfoxides 87 via arylation of general sulfinates 86.
Scheme 36: Plausible mechanism for the arylation of sulfinates 86 via sulfenates A to give diaryl sulfoxides 87...
Scheme 37: S-Arylation reactions of aryl or heterocyclic thiols 88.
Scheme 38: Site-selective S-arylation reactions of cysteine thiol groups in 91 and 94 in the presence of diary...
Scheme 39: The selective S-arylation of sulfenamides 97 using diphenyliodonium salts 98.
Scheme 40: Plausible mechanism for the synthesis of sulfilimines 99.
Scheme 41: Synthesis of S-arylxanthates 102 by reacting DAIS 101 with potassium alkyl xanthates 100.
Figure 2: Structured of the 8-membered and 4-membered heterotetramer I and II.
Scheme 42: S-Arylation by diaryliodonium cations 103 using KSCN (104) as a sulfur source.
Scheme 43: S-Arylation of phosphorothioate diesters 107 through the utilization of diaryliodonium salts 108.
Scheme 44: Transfer of the aryl group from the hypervalent iodonium salt 108 to phosphorothioate diester 107.
Scheme 45: Synthesis of diarylselenides 118 via diarylation of selenocyanate 115.
Scheme 46: Light-promoted arylation of tertiary phosphines 119 to quaternary phosphonium salts 121 using diary...
Scheme 47: Arylation of aminophosphorus substrate 122 to synthesize phosphine oxides 123 using aryl(mesityl)io...
Scheme 48: Reaction of diphenyliodonium triflate (16) with DMSO (124) via thia-Sommelet–Hauser rearrangement.
Scheme 49: Synthesis of biaryl compounds 132 by reacting diaryliodonium salts 131 with arylhydroxylamines 130 ...
Scheme 50: Synthesis of substituted indazoles 134 and 135 from N-hydroxyindazoles 133.
Beilstein J. Org. Chem. 2024, 20, 2883–2890, doi:10.3762/bjoc.20.242
Graphical Abstract
Scheme 1: State of the art and this work.
Scheme 2: Reaction conditions: hydrazone (0.3 mmol, 1.0 equiv), NBS (0.33 mmol, 1.1 equiv), in CH3CN (0.4 M),...
Scheme 3: Scope of the reaction. Reaction conditions: 1 (0.3 mmol, 1.0 equiv), NBS (0.33 mmol, 1.1 equiv) in ...
Scheme 4: Mechanistic investigations and post-functionalization reactions. a19F NMR yields using α,α,α-triflu...
Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178
Graphical Abstract
Scheme 1: Consecutive three-component synthesis of pyrazoles 1 via in situ-formed 1,3-diketones 2 [44].
Scheme 2: Consecutive three-component synthesis of 4-ethoxycarbonylpyrazoles 5 via SmCl3-catalyzed acylation ...
Scheme 3: Consecutive four-component synthesis of 1-(thiazol-2-yl)pyrazole-3-carboxylates 8 [51].
Scheme 4: Three-component synthesis of thiazolylpyrazoles 17 via in situ formation of acetoacetylcoumarins 18 ...
Scheme 5: Consecutive pseudo-four-component and four-component synthesis of pyrazoles 21 from sodium acetylac...
Scheme 6: Consecutive three-component synthesis of 1-substituted pyrazoles 24 from boronic acids, di(Boc)diim...
Scheme 7: Consecutive three-component synthesis of N-arylpyrazoles 25 via in situ formation of aryl-di(Boc)hy...
Scheme 8: Consecutive three-component synthesis of 1,3,4-substituted pyrazoles 27 and 28 from methylhydrazine...
Scheme 9: Consecutive three-component synthesis of 4-allylpyrazoles 32 via oxidative allylation of 1,3-dicarb...
Scheme 10: Pseudo-five-component synthesis of tris(pyrazolyl)methanes 35 [61].
Scheme 11: Pseudo-three-component synthesis of 5-(indol-3-yl)pyrazoles 39 from 1,3,5-triketones 38 [64].
Scheme 12: Three-component synthesis of thiazolylpyrazoles 43 [65].
Scheme 13: Three-component synthesis of triazolo[3,4-b]-1,3,4-thiadiazin-3-yl substituted 5-aminopyrazoles 47 [67]....
Scheme 14: Consecutive three-component synthesis of 5-aminopyrazoles 49 via formation of β-oxothioamides 50 [68].
Scheme 15: Synthesis of 3,4-biarylpyrazoles 52 from aryl halides, α-bromocinnamaldehyde, and tosylhydrazine vi...
Scheme 16: Consecutive three-component synthesis of 3,4-substituted pyrazoles 57 from iodochromones 55 by Suzu...
Scheme 17: Pseudo-four-component synthesis of pyrazolyl-2-pyrazolines 59 by ring opening/ring closing cyclocon...
Scheme 18: Consecutive three-component synthesis of pyrazoles 61 [77].
Scheme 19: Three-component synthesis of pyrazoles 62 from malononitrile, aldehydes, and hydrazines [78-90].
Scheme 20: Four-component synthesis of pyrano[2,3-c]pyrazoles 63 [91].
Scheme 21: Three-component synthesis of persubstituted pyrazoles 65 from aldehydes, β-ketoesters, and hydrazin...
Scheme 22: Three-component synthesis of pyrazol-4-carbodithioates 67 [100].
Scheme 23: Regioselective three-component synthesis of persubstituted pyrazoles 68 catalyzed by ionic liquid [...
Scheme 24: Consecutive three-component synthesis of 4-halopyrazoles 69 and anellated pyrazoles 70 [102].
Scheme 25: Three-component synthesis of 2,2,2-trifluoroethyl pyrazole-5-carboxylates 72 [103].
Scheme 26: Synthesis of pyrazoles 75 in a one-pot process via carbonylative Heck coupling and subsequent cycli...
Scheme 27: Copper-catalyzed three-component synthesis of 1,3-substituted pyrazoles 76 [105].
Scheme 28: Pseudo-three-component synthesis of bis(pyrazolyl)methanes 78 by ring opening-ring closing cyclocon...
Scheme 29: Three-component synthesis of 1,4,5-substituted pyrazoles 80 [107].
Scheme 30: Consecutive three-component synthesis of 3,5-bis(fluoroalkyl)pyrazoles 83 [111].
Scheme 31: Consecutive three-component synthesis of difluoromethanesulfonyl-functionalized pyrazole 88 [114].
Scheme 32: Consecutive three-component synthesis of perfluoroalkyl-substituted fluoropyrazoles 91 [115].
Scheme 33: Regioselective consecutive three-component synthesis of 1,3,5-substituted pyrazoles 93 [116].
Scheme 34: Three-component synthesis of pyrazoles 96 mediated by trimethyl phosphite [117].
Scheme 35: One-pot synthesis of pyrazoles 99 via Liebeskind–Srogl cross-coupling/cyclocondensation [118].
Scheme 36: Synthesis of 1,3,5-substituted pyrazoles 101 via domino condensation/Suzuki–Miyaura cross-coupling ...
Scheme 37: Consecutive three-component synthesis of 1,3,5-trisubstituted pyrazoles 102 and 103 by Sonogashira ...
Scheme 38: Polymer analogous consecutive three-component synthesis of pyrazole-based polymers 107 [132].
Scheme 39: Synthesis of 1,3,5-substituted pyrazoles 108 by sequentially Pd-catalyzed Kumada–Sonogashira cycloc...
Scheme 40: Consecutive four-step one-pot synthesis of 1,3,4,5-substituted pyrazoles 110 [137].
Scheme 41: Four-component synthesis of pyrazoles 113, 115, and 117 via Sonogashira coupling and subsequent Suz...
Scheme 42: Consecutive four- or five-component synthesis for the preparation of 4-pyrazoly-1,2,3-triazoles 119...
Scheme 43: Four-component synthesis of pyrazoles 121 via alkynone formation by carbonylative Pd-catalyzed coup...
Scheme 44: Preparation of 3-azulenyl pyrazoles 124 by glyoxylation, decarbonylative Sonogashira coupling, and ...
Scheme 45: Four-component synthesis of a 3-indoloylpyrazole 128 [147].
Scheme 46: Two-step synthesis of 5-acylpyrazoles 132 via glyoxylation-Stephen–Castro sequence and subsequent c...
Scheme 47: Copper on iron mediated consecutive three-component synthesis of 3,5-substituted pyrazoles 136 [150].
Scheme 48: Consecutive three-component synthesis of 3-substituted pyrazoles 141 by Sonogashira coupling and su...
Scheme 49: Consecutive three-component synthesis of pyrazoles 143 initiated by Cu(I)-catalyzed carboxylation o...
Scheme 50: Consecutive three-component synthesis of benzamide-substituted pyrazoles 146 starting from N-phthal...
Scheme 51: Consecutive three-component synthesis of 1,3,5-substituted pyrazoles 148 [156].
Scheme 52: Three-component synthesis of 4-ninhydrin-substituted pyrazoles 151 [158].
Scheme 53: Consecutive four-component synthesis of 4-(oxoindol)-1-phenylpyrazole-3-carboxylates 155 [159].
Scheme 54: Three-component synthesis of pyrazoles 160 [160].
Scheme 55: Consecutive three-component synthesis of pyrazoles 165 [162].
Scheme 56: Consecutive three-component synthesis of 3,5-disubstituted and 3-substituted pyrazoles 168 and 169 ...
Scheme 57: Three-component synthesis of 3,4,5-substituted pyrazoles 171 via 1,3-dipolar cycloaddition of vinyl...
Scheme 58: Three-component synthesis of pyrazoles 173 and 174 from aldehydes, tosylhydrazine, and vinylidene c...
Scheme 59: Three-component synthesis of pyrazoles 175 from glyoxyl hydrates, tosylhydrazine, and electron-defi...
Scheme 60: Pseudo-four-component synthesis of pyrazoles 177 from glyoxyl hydrates, tosylhydrazine, and aldehyd...
Scheme 61: Consecutive three-component synthesis of pyrazoles 179 via Knoevenagel-cycloaddition sequence [179].
Scheme 62: Three-component synthesis of 5-dimethylphosphonate substituted pyrazoles 182 from aldehydes, the Be...
Scheme 63: Consecutive three-component synthesis of 5-(dimethyl phosphonate)-substituted pyrazoles 185 from al...
Scheme 64: Three-component synthesis of 5-(dimethyl phosphonate)-substituted pyrazoles 187 from aldehydes, the...
Scheme 65: Three-component synthesis of 5-diethylphosphonate/5-phenylsulfonyl substituted pyrazoles 189 from a...
Scheme 66: Pseudo-three-component synthesis of 3-(dimethyl phosphonate)-substituted pyrazoles 190 [185].
Scheme 67: Three-component synthesis of 3-trifluoromethylpyrazoles 193 [186].
Scheme 68: Consecutive three-component synthesis of 5-stannyl-substituted 4-fluoropyrazole 197 [191,192].
Scheme 69: Pseudo-three-component synthesis of 3,5-diacyl-4-arylpyrazoles 199 [195].
Scheme 70: Three-component synthesis of pyrazoles 204 via nitrilimines [196].
Scheme 71: Three-component synthesis of 1,3,5-substituted pyrazoles 206 via formation of nitrilimines and sali...
Scheme 72: Pseudo four-component synthesis of pyrazoles 209 from acetylene dicarboxylates 147, hydrazonyl chlo...
Scheme 73: Consecutive three-component synthesis of pyrazoles 213 via syndnones 214 [200].
Scheme 74: Consecutive three-component synthesis of pyrazoles 216 via in situ-formed diazomethinimines 217 [201].
Scheme 75: Consecutive three-component synthesis of 3-methylthiopyrazoles 219 from aldehydes, hydrazine, and 1...
Scheme 76: Three-component synthesis of 1,3,5-substituted pyrazoles 220 from aldehydes, hydrazines, and termin...
Scheme 77: Three-component synthesis of 1,3,4,5-substituted pyrazoles 222 from aldehydes, hydrazines, and DMAD ...
Scheme 78: Pseudo three-component synthesis of pyrazoles 224 from sulfonyl hydrazone and benzyl acrylate under...
Scheme 79: Titanium-catalyzed consecutive four-component synthesis of pyrazoles 225 via enamino imines 226 [211]. a...
Scheme 80: Titanium-catalyzed three-component synthesis of pyrazoles 227 via enhydrazino imine complex interme...
Scheme 81: Pseudo-three-component synthesis of pyrazoles 229 via Glaser coupling of terminal alkynes and photo...
Scheme 82: Copper(II)acetate-mediated three-component synthesis of pyrazoles 232 [216].
Scheme 83: Copper-catalyzed three-component synthesis of 1,3,4-substituted pyrazole 234 from oxime acetates, a...
Scheme 84: Three-component synthesis of 3-trifluoroethylpyrazoles 239 [218].
Scheme 85: Pseudo-three-component synthesis of 1,4-bisulfonyl-substituted pyrazoles 242 [219].
Scheme 86: Three-component synthesis of 4-hydroxypyrazole 246 [221].
Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102
Graphical Abstract
Scheme 1: Ring cleavage and ring rearrangement reactions in the biosynthesis of atypical angucyclines.
Figure 1: HPLC traces of reaction mixtures of AlpG, AlpJ, Flu17, and JadG. (a) standards of prejadomycin (9),...
Figure 2: HPLC traces of reactions of JadG, AlpJ, or Flu17 quenched by SOD. (a) 8 + JadG + ʟ-isoleucine; (b) 8...
Scheme 2: Proposed catalytic mechanism of cofactor-independent AlpJ-family oxygenases.
Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59
Graphical Abstract
Scheme 1: Background (a and b) and proposed carboamination MCR with diazo esters (c). a) Selected bioactive γ...
Scheme 2: Substrate scope of diazo compounds, 1,3-dienes and amines. aReactions (1/2/3/Pd(OAc)2/Xantphos = 0....
Scheme 3: Substrate scope of diazo compounds, allenes and amines. aReactions (1/5/3/Pd(OAc)2/Xantphos = 0.3.0...
Scheme 4: Mechanistic experiments. a) Radical trapping experiments with TEMPO. b) Exclusion of possible inter...
Scheme 5: Proposed mechanisms for the carboamination of 1,3-dienes or allenes with diazo esters and amines.
Scheme 6: Scale-up reactions and synthetic transformations. Reaction conditions: a) LiAlH4, THF, 0 °C; b) MeM...
Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35
Graphical Abstract
Scheme 1: Comparison between Barton and NHPI ester radical precursors.
Scheme 2: Overview of the mechanisms and activation modes involved in radical generation from RAEs.
Scheme 3: Common mechanisms in photocatalysis.
Scheme 4: A) Giese-type radical addition of NHPI esters mediated by a reductive quenching photocatalytic cycl...
Scheme 5: A) Minisci-type radical addition of NHPI esters. B) Reaction mechanism involving an “off-cycle” red...
Scheme 6: Activation of NHPI esters through hydrogen-bonding in an oxidative quenching photocatalytic cycle.
Scheme 7: SET activation of RAE facilitated by a Lewis acid catalyst.
Scheme 8: PCET activation of NHPI esters in the context of a radical-redox annulation.
Scheme 9: Activation enabled by a strong excited-state reductant catalyst and its application in the dearomat...
Scheme 10: Proposed formation of an intramolecular charge-transfer complex in the synthesis of (spiro)anellate...
Scheme 11: Formation of a charge-transfer complex between enamides and NHPI esters enabled by a chiral phospha...
Scheme 12: Activation of NHPI ester through the formation of photoactive EDA-complexes.
Scheme 13: A) EDA complex-mediated radical hydroalkylation reactions of NHPI esters. B) Proposed mechanism for...
Scheme 14: Proposed radical chain mechanism initiated by EDA-complex formation.
Scheme 15: A) Photoinduced decarboxylative borylation. B) Proposed radical chain mechanism.
Scheme 16: A) Activation of NHPI esters mediated by PPh3/NaI. B) Proposed catalytic cycle involving EDA-comple...
Scheme 17: A) Radical generation facilitated by EDA complex formation between PTH1 catalyst and NHPI esters. B...
Scheme 18: Proposed catalytic cycle for the difunctionalization of styrenes.
Scheme 19: Formation of a charge-transfer complex between NHPI esters and Cs2CO3 enables decarboxylative amina...
Scheme 20: 3-Acetoxyquinuclidine as catalytic donor in the activation of TCNHPI esters.
Scheme 21: A) Photoinduced Cu-catalyzed decarboxylative amination. B) Proposed catalytic cycle. C) Radical clo...
Scheme 22: A) Photoinduced Pd-catalyzed aminoalkylation of 1,4-dienes. B) Proposed catalytic cycle.
Scheme 23: A) TM-catalyzed decarboxylative coupling of NHPI esters and organometallic reagents. B) Representat...
Scheme 24: Synthetic applications of the TM-catalyzed decarboxylative coupling of NHPI esters and organometall...
Scheme 25: A) Ni-catalyzed cross-electrophile coupling of NHPI esters. B) Representative catalytic cycle.
Scheme 26: A) Synthetic applications of decarboxylative cross-electrophile couplings. B) Decarboxylative aryla...
Scheme 27: A) Activation of tetrachlorophthalimide redox-active esters enabled by a low-valency Bi complex. B)...
Scheme 28: Activation of NHPI esters mediated by Zn0 applied in a Z-selective alkenylation reaction.
Scheme 29: A) Activation of NHPI esters enabled by a pyridine-boryl radical species applied to the decarboxyla...
Scheme 30: A) Decarboxylative coupling of RAE and aldehydes enabled by NHC-catalyzed radical relay. B) Propose...
Scheme 31: A) Decarboxylative C(sp3)–heteroatom coupling reaction of NHPI esters under NHC catalysis B) The NH...
Scheme 32: A) Electrochemical Giese-type radical addition of NHPI esters. B) Reaction mechanism.
Scheme 33: Electrochemical Minisci-type radical addition of NHPI-esters.
Scheme 34: Ni-electrocatalytic cross-electrophile coupling of NHPI esters with aryl iodides.
Scheme 35: A) Decarboxylative arylation of NHPI esters under Ag-Ni electrocatalysis B) Formation of AgNP on th...
Scheme 36: Synthetic applications of decarboxylative couplings of NHPI esters under Ni-electrocatalysis.
Scheme 37: Examples of natural product syntheses in which RAEs were used in key C–C bond forming reactions.
Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94
Graphical Abstract
Scheme 1: Research progress of coupling reactions and active compounds containing α-C(sp3)-functionalized eth...
Scheme 2: Transition-metal-catalyzed CDC pathways.
Scheme 3: CDC of active methylene compounds in the α-C(sp3) position of ethers.
Scheme 4: InCl3/Cu(OTf)2/NHPI co-catalyzed CDC reaction.
Scheme 5: CDC of cyclic benzyl ethers with aldehydes.
Scheme 6: Cu-catalyzed CDC of (a) unactivated C(sp3)–H ethers with simple ketones and (b) double C(sp3)−H fun...
Scheme 7: Cu-catalyzed CDC of C(sp3)–H/C(sp3)–H bonds.
Scheme 8: Cu-catalyzed synthesis of chiral 2-substituted tetrahydropyrans.
Scheme 9: CDC of thiazole with cyclic ethers.
Scheme 10: Cu(I)-catalyzed oxidative alkenylation of simple ethers.
Scheme 11: Cross-dehydrogenation coupling of isochroman C(sp3)–H bonds with anisole C(sp2)–H bonds.
Scheme 12: Pd(OAc)2/Cu(OTf)2-catalyzed arylation of α-C(sp3)–H bonds of ethers.
Scheme 13: Cu-catalyzed C(sp3)–H/C(sp2)–H activation strategies to construct C(sp3)–C(sp2) bonds.
Scheme 14: Cu(I)-catalyzed C(sp2)–H alkylation.
Scheme 15: Cu-catalyzed C(sp3)–H/C(sp)–H activation to construct C(sp3)–C(sp) bonds (H2BIP: 2,6-bis(benzimidaz...
Scheme 16: Fe-catalyzed CDC reaction pathways.
Scheme 17: Fe2(CO)9-catalyzed functionalization of C–H bonds.
Scheme 18: Ligand-promoted Fe-catalyzed CDC reaction of N-methylaniline with ethers.
Scheme 19: Fe-catalyzed CDC of C(sp3)–H/C(sp3)–H bonds.
Scheme 20: Fe-catalyzed hydroalkylation of α,β-unsaturated ketones with ethers.
Scheme 21: Solvent-free Fe(NO3)3-catalyzed CDC of C(sp3)–H/C(sp2)–H bonds.
Scheme 22: Alkylation of disulfide compounds to afford tetrasubstituted alkenes.
Scheme 23: Fe-catalyzed formation of 1,1-bis-indolylmethane derivatives.
Scheme 24: Alkylation of coumarins and flavonoids.
Scheme 25: Direct CDC α-arylation of azoles with ethers.
Scheme 26: CDC of terminal alkynes with C(sp3)–H bonds adjacent to oxygen, sulfur or nitrogen atoms.
Scheme 27: Alkylation of terminal alkynes.
Scheme 28: Co-catalyzed functionalization of glycine esters.
Scheme 29: Co-catalyzed construction of C(sp2)–C(sp3) bonds.
Scheme 30: Co-catalyzed CDC of imidazo[1,2-a]pyridines with isochroman.
Scheme 31: Co-catalyzed C–H alkylation of (benz)oxazoles with ethers.
Scheme 32: Cobalt-catalyzed CDC between unactivated C(sp2)–H and C(sp3)–H bonds.
Scheme 33: MnO2-catalyzed CDC of the inactive C(sp3)-H.
Scheme 34: Oxidative cross-coupling of ethers with enamides.
Scheme 35: Ni(II)-catalyzed CDC of indoles with 1,4-dioxane.
Scheme 36: Chemo- and regioselective ortho- or para-alkylation of pyridines.
Scheme 37: Asymmetric CDC of 3,6-dihydro-2H-pyrans with aldehydes.
Scheme 38: CDC of heterocyclic aromatics with ethers.
Scheme 39: Indium-catalyzed alkylation of DHPs with 1,3-dicarbonyl compounds.
Scheme 40: Rare earth-metal-catalyzed CDC reaction.
Scheme 41: Visible-light-driven CDC of cycloalkanes with benzazoles.
Scheme 42: Photoinduced alkylation of quinoline with cyclic ethers.
Scheme 43: Photocatalyzed CDC reactions between α-C(sp3)–H bonds of ethers and C(sp2)–H bonds of aromatics.
Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81
Graphical Abstract
Figure 1: Oxidative and reductive activations of organic compounds harvesting photoredox catalysis.
Figure 2: General catalytic cycles of radical ion conPET (left) and radical ion e-PRC (right).
Figure 3: “Beginner’s guide”: comparison between advantages, capacities, and prospectives of conPET and PEC.
Figure 4: A) conPET reductive dehalogenation of aryl halides with PDI. B) Reductive C–H arylation with pyrrol...
Figure 5: A) Chromoselective mono- and disubstitution or polybrominated pyrimidines with pyrroles. B) Sequent...
Figure 6: A) Synthesis of pyrrolo[1,2-a]quinolines. B) Synthesis of ullazines.
Figure 7: A) Reductive phosphorylation of aryl halides via conPET. B) Selected examples from the substrate sc...
Figure 8: A) Reductive dehalogenation of aryl halides via conPET and selected examples from the substrate sco...
Figure 9: A) Reductive C–H arylation of aryl halides via conPET (top) and selected examples from the substrat...
Figure 10: A) Reductive hydrodehalogenation of aryl halides with Mes-Acr-BF4. B) Selected examples from the su...
Figure 11: A) Reductive hydrodechlorination of aryl chlorides with 4-DPAIPN. B) Proposed formation of CO2•−. C...
Figure 12: A) Reductive conPET borylation with 3CzEPAIPN (top) and selected examples from the substrate scope ...
Figure 13: Scale-up of conPET phosphorylation with 3CzEPAIPN.
Figure 14: A) Borylation of 1d. B) Characteristics and structure of PC1 with green and red parts showing the l...
Figure 15: A) Reductive C–H arylation scope with polysulfide conPET (top) and selected examples from the subst...
Figure 16: Scale-up of A) C–H arylation and B) dehaloborylation with polysulfide photocatalysis in continuous-...
Figure 17: A) Formation of [Ir1]0 and [Ir2]0 upon PET between [Ir1]+ and Et3N. B) Mechanism of multi-photon ta...
Figure 18: A) Reductive hydrodehalogenation of aryl halides via multi-photon tandem photocatalysis. B) Selecte...
Figure 19: A) Carbonylative amidation of aryl halides in continuous flow. B) Selected examples from the substr...
Figure 20: A) General scheme for reductive (RQ) and oxidative quenching (OQ) protocols using [FeIII(btz)3](PF6)...
Figure 21: A) Carbonylative amidation of alkyl iodides with [IrIII(ppy)2(dtbbpy)]PF6. B) Selected examples fro...
Figure 22: A) Carboxylative C–N bond cleavage in cyclic amines. B) Selected examples from the substrate scope....
Figure 23: A) Formal reduction of alkenes to alkanes via transfer hydrogenation. B) Selected examples from the...
Figure 24: A) Birch-type reduction of benzenes with PMP-BPI. B) Selected examples from the substrate scope (sc...
Figure 25: Proposed mechanism of the OH− mediated conPET Birch-type reduction of benzene via generation of sol...
Figure 26: Reductive detosylation of N-tosylated amides with Mes-Acr-BF4. B) Selected examples from the substr...
Figure 27: A) Reductive detosylation of N-tosyl amides by dual PRC. B) Selected examples from the substrate sc...
Figure 28: A) Mechanism of the dual PRC based on PET between [Cu(dap)2]+ and DCA. B) Mechanism of the dual PRC...
Figure 29: A) N–O bond cleavage in Weinreb amides with anthracene. B) N–O bond cleavage in Weinreb amides rely...
Figure 30: A) Pentafluorosulfanylation and fluoride elimination. B) Mechanism of the pentafluorosulfanylation ...
Figure 31: A) α-Alkoxypentafluorosulfanylation (top) and selected examples from the substrate scope (bottom). ...
Figure 32: A) Oxidative amination of arenes with azoles catalyzed by N-Ph PTZ. B) Selected examples from the s...
Figure 33: A) C(sp3)–H bond activation by HAT via chloride oxidation by *N-Ph PTZ•+. B) Proposed mechanism for...
Figure 34: A) Recycling e-PRC C–H azolation of electron-rich arenes with pyrazoles using Mes-Acr+ as a photoca...
Figure 35: A) Radical ion e-PRC direct oxidation of unactivated arenes using TAC+ as an electro-activated phot...
Figure 36: A) Radical ion e-PRC direct oxidation of unactivated arenes using TPA as an electro-activated photo...
Figure 37: Proposed mechanism (top) and mode of preassembly (bottom).
Figure 38: A) Possible preassemblies of reactive (left) vs unreactive (right) arenes. B) Calculated spin densi...
Figure 39: A) Recycling e-PRC C(sp2 )–H acetoxylation of arenes using DDQ as a photocatalyst. B) Proposed cata...
Figure 40: Gram scale hydroxylation of benzene in a recirculated flow setup.
Figure 41: A) Radical ion e-PRC vicinal diamination of alkylarenes using TAC+ as an electro-activated photocat...
Figure 42: A) Sequential oxygenation of multiple adjacent C–H bonds under radical ion e-PRC using TAC+ as an e...
Figure 43: A) Enantioselective recycling e-PRC cyanation of benzylic C–H bonds using ADQS as photocatalyst. B)...
Figure 44: Proposed tandem mechanism by Xu and co-workers.
Figure 45: A) Enantioselective recycling e-PRC decarboxylative cyanation using Cu(acac)2, Ce(OTf)3 and a box l...
Figure 46: A) Enantioselective recycling e-PRC benzylic cyanation using Cu(MeCN)4BF4, box ligand and anthraqui...
Figure 47: A) Radical ion e-PRC acetoxyhydroxylation of aryl olefins using TAC+ as an electro-activated photoc...
Figure 48: Selected examples from the substrate scope.
Figure 49: Photoelectrochemical acetoxyhydroxylation in a recirculated flow setup.
Figure 50: A) Radical ion e-PRC aminooxygenation of aryl olefins using TAC+ as an electro-activated photocatal...
Figure 51: A) Recycling e-PRC C–H alkylation of heteroarenes with organic trifluoroborates using Mes-Acr+ as p...
Figure 52: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using CeCl3·7H2O as catalyst. B) ...
Figure 53: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using Fe(NH4)2(SO4)2·6H2O as cata...
Figure 54: A) Recycling e-PRC C–H alkylation of heteroarenes with alkyl oxalates and 4CzIPN as photocatalyst. ...
Figure 55: A) Recycling e-PRC decarboxylative C–H carbamoylation of heteroarenes using 4CzIPN as photocatalyst...
Figure 56: A) Photoelectrochemical HAT-mediated hydrocarbon activation via the chlorine radical. B) Proposed m...
Figure 57: A) Selected examples from the substrate scope. B) Gram and decagram scale semi-continuous flow PEC ...
Figure 58: A) Photoelectrochemical HAT-mediated dehydrogenative coupling of benzothiazoles with aliphatic C–H ...
Figure 59: A) Photoelectrochemical HAT activation of ethers using electro-activated TAC+ as photocatalyst. B) ...
Figure 60: Selected examples from the substrate scope.
Figure 61: A) Photoelectrochemical HAT-mediated synthesis of alkylated benzimidazo-fused isoquinolinones using...
Figure 62: A) Decoupled photoelectrochemical cerium-catalyzed oxydichlorination of alkynes using CeCl3 as cata...
Figure 63: Proposed decoupled photoelectrochemical mechanism.
Figure 64: A) Decoupled photoelectrochemical ring-opening bromination of tertiary cycloalkanols using MgBr2 as...
Figure 65: A) Recycling e-PRC ring-opening functionalization of cycloalkanols using CeCl3 as catalyst. B) Prop...
Figure 66: Selected examples from the substrate scope of the PEC ring-opening functionalization.
Figure 67: A) Radical ion e-PRC reduction of chloro- and bromoarenes using DCA as catalyst and various accepto...
Figure 68: A) Screening of different phthalimide derivatives as catalyst for the e-PRC reduction of aryl halid...
Figure 69: Screening of different organic catalysts for the e-PRC reduction of trialkylanilium salts.
Figure 70: A) e-PRC reduction of phosphonated phenols and anilinium salts. B) Selected examples from the subst...
Figure 71: A) ConPET and e-PRC reduction of 4-bromobenzonitrile using a naphthalene diimide (NDI) precatalyst ...
Figure 72: A) Radical ion e-PRC reduction of phosphinated aliphatic alcohols with n-BuO-NpMI as catalyst. B) C...
Figure 73: Selected examples from the substrate scope.
Figure 74: A) Recycling e-PRC reductive dimerization of benzylic chlorides using a [Cu2] catalyst. B) Proposed...
Figure 75: A) Decoupled photoelectrochemical C–H alkylation of heteroarenes through deamination of Katritzky s...
Figure 76: Proposed mechanism by Chen and co-workers.
Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5
Graphical Abstract
Figure 1: Representative natural products and biologically active molecules containing an oxindole moiety [7-13].
Scheme 1: Selected photocatalytic decarboxylative radical cascade reactions of N-arylamides.
Scheme 2: Arylamide substrate scope with isolated yields of products.
Scheme 3: Alkyl radical precursor scope with isolated yields of products.
Scheme 4: Selected mechanistic experiments.
Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1
Graphical Abstract
Scheme 1: The power of radical retrosynthesis and the tactic of divergent total synthesis.
Figure 1: Evolution of radical chemistry for organic synthesis.
Scheme 2: Divergent total synthesis of α-pyrone-diterpenoids (Baran).
Scheme 3: Divergent synthesis of pyrone diterpenoids by merged chemoenzymatic and radical synthesis (part I, ...
Scheme 4: Divergent synthesis of pyrone diterpenoids by merged chemoenzymatic and radical synthesis (part II,...
Scheme 5: Divergent synthesis of drimane-type hydroquinone meroterpenoids (Li).
Scheme 6: Divergent synthesis of natural products isolated from Dysidea avara (Lu).
Scheme 7: Divergent synthesis of kaurene-type terpenoids (Lei).
Scheme 8: Divergent synthesis of 6-oxabicyclo[3.2.1]octane meroterpenoids (Lou).
Scheme 9: Divergent synthesis of crinipellins by radical-mediated Dowd–Backwith rearrangement (Xie and Ding).
Scheme 10: Divergent total synthesis of Galbulimima alkaloids (Shenvi).
Scheme 11: Divergent synthesis of eburnane alkaloids (Qin).
Scheme 12: Divergent synthesis of Aspidosperma alkaloids (Boger).
Scheme 13: Photoredox based synthesis of (−)-FR901483 (160) and (+)-TAN1251C (162, Gaunt).
Scheme 14: Divergent synthesis of bipolamines (Maimone).
Scheme 15: Flow chemistry divergency between aporphine and morphinandione alkaloids (Felpin).
Scheme 16: Divergent synthesis of pyrroloazocine natural products (Echavarren).
Scheme 17: Using TEMPO to stabilize radicals for the divergent synthesis of pyrroloindoline natural products (...
Scheme 18: Radical pathway for preparation of lignans (Zhu).
Scheme 19: Divergent synthesis of DBCOD lignans (Lumb).
Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196
Graphical Abstract
Figure 1: Price comparison among iron and other transition metals used in catalysis.
Scheme 1: Typical modes of C–C bond formation.
Scheme 2: The components of an iron-catalyzed domino reaction.
Scheme 3: Iron-catalyzed tandem cyclization and cross-coupling reactions of iodoalkanes 1 with aryl Grignard ...
Scheme 4: Three component iron-catalyzed dicarbofunctionalization of vinyl cyclopropanes 14.
Scheme 5: Three-component iron-catalyzed dicarbofunctionalization of alkenes 21.
Scheme 6: Double carbomagnesiation of internal alkynes 31 with alkyl Grignard reagents 32.
Scheme 7: Iron-catalyzed cycloisomerization/cross-coupling of enyne derivatives 35 with alkyl Grignard reagen...
Scheme 8: Iron-catalyzed spirocyclization/cross-coupling cascade.
Scheme 9: Iron-catalyzed alkenylboration of alkenes 50.
Scheme 10: N-Alkyl–N-aryl acrylamide 60 CDC cyclization with C(sp3)–H bonds adjacent to a heteroatom.
Scheme 11: 1,2-Carboacylation of activated alkenes 60 with aldehydes 65 and alcohols 67.
Scheme 12: Iron-catalyzed dicarbonylation of activated alkenes 68 with alcohols 67.
Scheme 13: Iron-catalyzed cyanoalkylation/radical dearomatization of acrylamides 75.
Scheme 14: Synergistic photoredox/iron-catalyzed 1,2-dialkylation of alkenes 82 with common alkanes 83 and 1,3...
Scheme 15: Iron-catalyzed oxidative coupling/cyclization of phenol derivatives 86 and alkenes 87.
Scheme 16: Iron-catalyzed carbosulfonylation of activated alkenes 60.
Scheme 17: Iron-catalyzed oxidative spirocyclization of N-arylpropiolamides 91 with silanes 92 and tert-butyl ...
Scheme 18: Iron-catalyzed free radical cascade difunctionalization of unsaturated benzamides 94 with silanes 92...
Scheme 19: Iron-catalyzed cyclization of olefinic dicarbonyl compounds 97 and 100 with C(sp3)–H bonds.
Scheme 20: Radical difunctionalization of o-vinylanilides 102 with ketones and esters 103.
Scheme 21: Dehydrogenative 1,2-carboamination of alkenes 82 with alkyl nitriles 76 and amines 105.
Scheme 22: Iron-catalyzed intermolecular 1,2-difunctionalization of conjugated alkenes 107 with silanes 92 and...
Scheme 23: Four-component radical difunctionalization of chemically distinct alkenes 114/115 with aldehydes 65...
Scheme 24: Iron-catalyzed carbocarbonylation of activated alkenes 60 with carbazates 117.
Scheme 25: Iron-catalyzed radical 6-endo cyclization of dienes 119 with carbazates 117.
Scheme 26: Iron-catalyzed decarboxylative synthesis of functionalized oxindoles 130 with tert-butyl peresters ...
Scheme 27: Iron‑catalyzed decarboxylative alkylation/cyclization of cinnamamides 131/134.
Scheme 28: Iron-catalyzed carbochloromethylation of activated alkenes 60.
Scheme 29: Iron-catalyzed trifluoromethylation of dienes 142.
Scheme 30: Iron-catalyzed, silver-mediated arylalkylation of conjugated alkenes 115.
Scheme 31: Iron-catalyzed three-component carboazidation of conjugated alkenes 115 with alkanes 101/139b and t...
Scheme 32: Iron-catalyzed carboazidation of alkenes 82 and alkynes 160 with iodoalkanes 20 and trimethylsilyl ...
Scheme 33: Iron-catalyzed asymmetric carboazidation of styrene derivatives 115.
Scheme 34: Iron-catalyzed carboamination of conjugated alkenes 115 with alkyl diacyl peroxides 163 and acetoni...
Scheme 35: Iron-catalyzed carboamination using oxime esters 165 and arenes 166.
Scheme 36: Iron-catalyzed iminyl radical-triggered [5 + 2] and [5 + 1] annulation reactions with oxime esters ...
Scheme 37: Iron-catalyzed decarboxylative alkyl etherification of alkenes 108 with alcohols 67 and aliphatic a...
Scheme 38: Iron-catalyzed inter-/intramolecular alkylative cyclization of carboxylic acid and alcohol-tethered...
Scheme 39: Iron-catalyzed intermolecular trifluoromethyl-acyloxylation of styrene derivatives 115.
Scheme 40: Iron-catalyzed carboiodination of terminal alkenes and alkynes 180.
Scheme 41: Copper/iron-cocatalyzed cascade perfluoroalkylation/cyclization of 1,6-enynes 183/185.
Scheme 42: Iron-catalyzed stereoselective carbosilylation of internal alkynes 187.
Scheme 43: Synergistic photoredox/iron catalyzed difluoroalkylation–thiolation of alkenes 82.
Scheme 44: Iron-catalyzed three-component aminoazidation of alkenes 82.
Scheme 45: Iron-catalyzed intra-/intermolecular aminoazidation of alkenes 194.
Scheme 46: Stereoselective iron-catalyzed oxyazidation of enamides 196 using hypervalent iodine reagents 197.
Scheme 47: Iron-catalyzed aminooxygenation for the synthesis of unprotected amino alcohols 200.
Scheme 48: Iron-catalyzed intramolecular aminofluorination of alkenes 209.
Scheme 49: Iron-catalyzed intramolecular aminochlorination and aminobromination of alkenes 209.
Scheme 50: Iron-catalyzed intermolecular aminofluorination of alkenes 82.
Scheme 51: Iron-catalyzed aminochlorination of alkenes 82.
Scheme 52: Iron-catalyzed phosphinoylazidation of alkenes 108.
Scheme 53: Synergistic photoredox/iron-catalyzed three-component aminoselenation of trisubstituted alkenes 82.
Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143
Graphical Abstract
Scheme 1: Nickel-catalyzed cross-coupling versus C‒H activation.
Figure 1: Oxidative and reductive quenching cycles of a photocatalyst. [PC] = photocatalyst, A = acceptor, D ...
Scheme 2: Photoredox nickel-catalyzed C(sp3)–H arylation of dimethylaniline (1a).
Scheme 3: Photoredox nickel-catalyzed arylation of α-amino, α-oxy and benzylic C(sp3)‒H bonds with aryl bromi...
Figure 2: Proposed catalytic cycle for the photoredox-mediated HAT and nickel catalysis enabled C(sp3)‒H aryl...
Scheme 4: Photoredox arylation of α-amino C(sp3)‒H bonds with aryl iodides.
Figure 3: Proposed mechanism for photoredox nickel-catalyzed α-amino C‒H arylation with aryl iodides.
Scheme 5: Nickel-catalyzed α-oxy C(sp3)−H arylation of cyclic and acyclic ethers.
Figure 4: Proposed catalytic cycle for the C(sp3)−H arylation of cyclic and acyclic ethers.
Scheme 6: Photochemical nickel-catalyzed C–H arylation of ethers.
Figure 5: Proposed catalytic cycle for the nickel-catalyzed arylation of ethers with aryl bromides.
Scheme 7: Nickel-catalyzed α-amino C(sp3)‒H arylation with aryl tosylates.
Scheme 8: Arylation of α-amino C(sp3)‒H bonds by in situ generated aryl tosylates from phenols.
Scheme 9: Formylation of aryl chlorides through redox-neutral 2-functionalization of 1,3-dioxolane (13).
Scheme 10: Photochemical C(sp3)–H arylation via a dual polyoxometalate HAT and nickel catalytic manifold.
Figure 6: Proposed mechanism for C(sp3)–H arylation through dual polyoxometalate HAT and nickel catalytic man...
Scheme 11: Photochemical nickel-catalyzed α-hydroxy C‒H arylation.
Scheme 12: Photochemical synthesis of fluoxetine (21).
Scheme 13: Photochemical nickel-catalyzed allylic C(sp3)‒H arylation with aryl bromides.
Figure 7: Proposed mechanism for the photochemical nickel-catalyzed allylic C(sp3)‒H arylation with aryl brom...
Scheme 14: Photochemical C(sp3)‒H arylation by the synergy of ketone HAT catalysis and nickel catalysis.
Figure 8: Proposed mechanism for photochemical C(sp3)‒H arylation by the synergy of ketone HAT catalysis and ...
Scheme 15: Benzophenone- and nickel-catalyzed photoredox benzylic C–H arylation.
Scheme 16: Benzaldehyde- and nickel-catalyzed photoredox C(sp3)–H arylation.
Scheme 17: Photoredox and nickel-catalyzed enantioselective benzylic C–H arylation.
Figure 9: Proposed mechanism for the photoredox and nickel-catalyzed enantioselective benzylic C–H arylation.
Scheme 18: Photoredox nickel-catalyzed α-(sp3)‒H arylation of secondary benzamides with aryl bromides.
Scheme 19: Enantioselective sp3 α-arylation of benzamides.
Scheme 20: Nickel-catalyzed decarboxylative vinylation/C‒H arylation of cyclic oxalates.
Figure 10: Proposed mechanism for the nickel-catalyzed decarboxylative vinylation/C‒H arylation of cyclic oxal...
Scheme 21: C(sp3)−H arylation of bioactive molecules using mpg-CN photocatalysis and nickel catalysis.
Figure 11: Proposed mechanism for the mpg-CN/nickel photocatalytic C(sp3)–H arylation.
Scheme 22: Nickel-catalyzed synthesis of 1,1-diarylalkanes from alkyl bromides and aryl bromides.
Figure 12: Proposed mechanism for photoredox nickel-catalyzed C(sp3)–H alkylation via polarity-matched HAT.
Scheme 23: Photoredox nickel-catalyzed C(sp3)‒H alkylation via polarity-matched HAT.
Scheme 24: Benzaldehyde- and nickel-catalyzed photoredox C(sp3)‒H alkylation of ethers.
Scheme 25: Benzaldehyde- and nickel-catalyzed photoredox C(sp3)‒H alkylation of amides and thioethers.
Scheme 26: Photoredox and nickel-catalyzed C(sp3)‒H alkylation of benzamides with alkyl bromides.
Scheme 27: CzIPN and nickel-catalyzed C(sp3)‒H alkylation of ethers with alkyl bromides.
Figure 13: Proposed mechanism for the CzIPN and nickel-catalyzed C(sp3)‒H alkylation of ethers.
Scheme 28: Nickel/photoredox-catalyzed methylation of (hetero)aryl chlorides and acid chlorides using trimethy...
Figure 14: Proposed catalytic cycle for the nickel/photoredox-catalyzed methylation of (hetero)aryl chlorides ...
Scheme 29: Photochemical nickel-catalyzed C(sp3)–H methylations.
Scheme 30: Photoredox nickel catalysis-enabled alkylation of unactivated C(sp3)–H bonds with alkyl bromides.
Scheme 31: Photochemical C(sp3)–H alkenylation with alkenyl tosylates.
Scheme 32: Photoredox nickel-catalyzed hydroalkylation of internal alkynes.
Figure 15: Proposed mechanism for the photoredox nickel-catalyzed hydroalkylation of internal alkynes.
Scheme 33: Photoredox nickel-catalyzed hydroalkylation of activated alkynes with C(sp3)−H bonds.
Scheme 34: Allylation of unactivated C(sp3)−H bonds with allylic chlorides.
Scheme 35: Photochemical nickel-catalyzed α-amino C(sp3)–H allylation of secondary amides with trifluoromethyl...
Scheme 36: Photoredox δ C(sp3)‒H allylation of secondary amides with trifluoromethylated alkenes.
Scheme 37: Photoredox nickel-catalyzed acylation of α-amino C(sp3)‒H bonds of N-arylamines.
Figure 16: Proposed mechanism for the photoredox nickel-catalyzed acylation of α-amino C(sp3)–H bonds of N-ary...
Scheme 38: Photocatalytic α‑acylation of ethers with acid chlorides.
Figure 17: Proposed mechanism for the photocatalytic α‑acylation of ethers with acid chlorides.
Scheme 39: Photoredox and nickel-catalyzed C(sp3)‒H esterification with chloroformates.
Scheme 40: Photoredox nickel-catalyzed dehydrogenative coupling of benzylic and aldehydic C–H bonds.
Figure 18: Proposed reaction pathway for the photoredox nickel-catalyzed dehydrogenative coupling of benzylic ...
Scheme 41: Photoredox nickel-catalyzed enantioselective acylation of α-amino C(sp3)–H bonds with carboxylic ac...
Scheme 42: Nickel-catalyzed C(sp3)‒H acylation with N-acylsuccinimides.
Figure 19: Proposed mechanism for the nickel-catalyzed C(sp3)–H acylation with N-acylsuccinimides.
Scheme 43: Nickel-catalyzed benzylic C–H functionalization with acid chlorides 45.
Scheme 44: Photoredox nickel-catalyzed benzylic C–H acylation with N-acylsuccinimides 84.
Scheme 45: Photoredox nickel-catalyzed acylation of indoles 86 with α-oxoacids 87.
Scheme 46: Nickel-catalyzed aldehyde C–H functionalization.
Figure 20: Proposed catalytic cycle for the photoredox nickel-catalyzed aldehyde C–H functionalization.
Scheme 47: Photoredox carboxylation of methylbenzenes with CO2.
Figure 21: Proposed mechanism for the photoredox carboxylation of methylbenzenes with CO2.
Scheme 48: Decatungstate photo-HAT and nickel catalysis enabled alkene difunctionalization.
Figure 22: Proposed catalytic cycle for the decatungstate photo-HAT and nickel catalysis enabled alkene difunc...
Scheme 49: Diaryl ketone HAT catalysis and nickel catalysis enabled dicarbofunctionalization of alkenes.
Figure 23: Proposed catalytic mechanism for the diaryl ketone HAT catalysis and nickel catalysis enabled dicar...
Scheme 50: Overview of photoredox nickel-catalyzed C–H functionalizations.
Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93
Graphical Abstract
Figure 1: Icilio Guareschi (1847–1918). (Source: Annali della Reale Accademia di Agricoltura di Torino 1919, ...
Scheme 1: Vitamin B6 (pyridoxine, 1), gabapentin (2), and thymol (3).
Figure 2: Baliatico (Nursing) by Francesco Scaramuzza (275 cm × 214 cm, Parma, Complesso Museale della Pilott...
Figure 3: Schiff’s fictitious report on the foundation of the Gazzetta Chimica Italiana (Image reproduced fro...
Scheme 2: Reaction of thymol (3) with chloroform under the basic conditions of the Guareschi–Lustgarten react...
Figure 4: The chemistry building of Turin University in a historical picture. Note, that one of the “mysterio...
Scheme 3: Triacetonamine (6) and the related compounds phorone (7), α-eucaine (8), and tropinone (9).
Scheme 4: Taxonomy of the Guareschi pyridone syntheses.
Scheme 5: The catalytic cycle of the “1897 reaction”.
Scheme 6: Resonance forms of the radical 10.
Figure 5: The wet chamber used by Guareschi to restore parchments (Gorrini, G. L'incendio della R. Biblioteca...
Figure 6: The Guareschi mask. (Servizio Chimico Militare. L'opera di Icilio Guareschi precursore della masche...
Figure 7: Guareschi’s bust at the Dipartimento di Scienza e Tecnologia del Farmaco of Turin University. Permi...
Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25
Graphical Abstract
Scheme 1: Synthesis of 1,1-difluoro-2,3-dimethylcyclopropane (2).
Scheme 2: Cyclopropanation via dehydrohalogenation of chlorodifluoromethane.
Scheme 3: Difluorocyclopropanation of methylstyrene 7 using dibromodifluoromethane and zinc.
Scheme 4: Synthesis of difluorocyclopropanes from the reaction of dibromodifluoromethane and triphenylphosphi...
Scheme 5: Generation of difluorocarbene in a catalytic two-phase system and its addition to tetramethylethyle...
Scheme 6: The reaction of methylstyrene 7 with chlorodifluoromethane (11) in the presence of a tetraarylarson...
Scheme 7: Pyrolysis of sodium chlorodifluoroacetate (12) in refluxing diglyme in the presence of alkene 13.
Scheme 8: Synthesis of boron-substituted gem-difluorocyclopropanes 16.
Scheme 9: Addition of sodium bromodifluoroacetate (17) to alkenes.
Scheme 10: Addition of sodium bromodifluoroacetate (17) to silyloxy-substituted cyclopropanes 20.
Scheme 11: Synthesis of difluorinated nucleosides.
Scheme 12: Addition of butyl acrylate (26) to difluorocarbene generated from TFDA (25).
Scheme 13: Addition of difluorocarbene to propargyl esters 27 and conversion of the difluorocyclopropenes 28 t...
Scheme 14: The generation of difluorocyclopropanes using MDFA 30.
Scheme 15: gem-Difluorocyclopropanation of styrene (32) using difluorocarbene generated from TMSCF3 (31) under...
Scheme 16: Synthesis of a gem-difluorocyclopropane derivative using HFPO (41) as a source of difluorocarbene.
Scheme 17: Cyclopropanation of (Z)-2-butene in the presence of difluorodiazirine (44).
Scheme 18: The cyclopropanation of 1-octene (46) using Seyferth's reagent (45) as a source of difluorocarbene.
Scheme 19: Alternative approaches for the difluorocarbene synthesis from trimethyl(trifluoromethyl)tin (48).
Scheme 20: Difluorocyclopropanation of cyclohexene (49).
Scheme 21: Synthesis of difluorocyclopropane derivative 53 using bis(trifluoromethyl)cadmium (51) as the diflu...
Scheme 22: Addition of difluorocarbene generated from tris(trifluoromethyl)bismuth (54).
Scheme 23: Addition of a stable (trifluoromethyl)zinc reagent to styrenes.
Scheme 24: The preparation of 2,2-difluorocyclopropanecarboxylic acids of type 58.
Scheme 25: Difluorocyclopropanation via Michael cyclization.
Scheme 26: Difluorocyclopropanation using N-acylimidazolidinone 60.
Scheme 27: Difluorocyclopropanation through the cyclization of phenylacetonitrile (61) and 1,2-dibromo-1,1-dif...
Scheme 28: gem-Difluoroolefins 64 for the synthesis of functionalized cyclopropanes 65.
Scheme 29: Preparation of aminocyclopropanes 70.
Scheme 30: Synthesis of fluorinated methylenecyclopropane 74 via selenoxide elimination.
Scheme 31: Reductive dehalogenation of (1R,3R)-75.
Scheme 32: Synthesis of chiral monoacetates by lipase catalysis.
Scheme 33: Transformation of (±)-trans-81 using Rhodococcus sp. AJ270.
Scheme 34: Transformation of (±)-trans-83 using Rhodococcus sp. AJ270.
Scheme 35: Hydrogenation of difluorocyclopropenes through enantioselective hydrocupration.
Scheme 36: Enantioselective transfer hydrogenation of difluorocyclopropenes with a Ru-based catalyst.
Scheme 37: The thermal transformation of trans-1,2-dichloro-3,3-difluorocyclopropane (84).
Scheme 38: cis–trans-Epimerization of 1,1-difluoro-2,3-dimethylcyclopropane.
Scheme 39: 2,2-Difluorotrimethylene diradical intermediate.
Scheme 40: Ring opening of stereoisomers 88 and 89.
Scheme 41: [1,3]-Rearrangement of alkenylcyclopropanes 90–92.
Scheme 42: Thermolytic rearrangement of 2,2-difluoro-1-vinylcyclopropane (90).
Scheme 43: Thermal rearrangement for ethyl 3-(2,2-difluoro)-3-phenylcyclopropyl)acrylates 93 and 95.
Scheme 44: Possible pathways of the ring opening of 1,1-difluoro-2-vinylcyclopropane.
Scheme 45: Equilibrium between 1,1-difluoro-2-methylenecyclopropane (96) and (difluoromethylene)cyclopropane 97...
Scheme 46: Ring opening of substituted 1,1-difluoro-2,2-dimethyl-3-methylenecyclopropane 98.
Scheme 47: 1,1-Difluorospiropentane rearrangement.
Scheme 48: Acetolysis of (2,2-difluorocyclopropyl)methyl tosylate (104) and (1,1-difluoro-2-methylcyclopropyl)...
Scheme 49: Ring opening of gem-difluorocyclopropyl ketones 106 and 108 by thiolate nucleophiles.
Scheme 50: Hydrolysis of gem-difluorocyclopropyl acetals 110.
Scheme 51: Ring-opening reaction of 2,2-difluorocyclopropyl ketones 113 in the presence of ionic liquid as a s...
Scheme 52: Ring opening of gem-difluorocyclopropyl ketones 113a by MgI2-initiated reaction with diarylimines 1...
Scheme 53: Ring-opening reaction of gem-difluorocyclopropylstannanes 117.
Scheme 54: Preparation of 1-fluorovinyl vinyl ketone 123 and the synthesis of 2-fluorocyclopentenone 124. TBAT...
Scheme 55: Iodine atom-transfer ring opening of 1,1-difluoro-2-(1-iodoalkyl)cyclopropanes 125a–c.
Scheme 56: Ring opening of bromomethyl gem-difluorocyclopropanes 130 and formation of gem-difluoromethylene-co...
Scheme 57: Ring-opening aerobic oxidation reaction of gem-difluorocyclopropanes 132.
Scheme 58: Dibrominative ring-opening functionalization of gem-difluorocyclopropanes 134.
Scheme 59: The selective formation of (E,E)- and (E,Z)-fluorodienals 136 and 137 from difluorocyclopropyl acet...
Scheme 60: Proposed mechanism for the reaction of difluoro(methylene)cyclopropane 139 with Br2.
Scheme 61: Thermal rearrangement of F2MCP 139 and iodine by CuI catalysis.
Scheme 62: Synthesis of 2-fluoropyrroles 142.
Scheme 63: Ring opening of gem-difluorocyclopropyl ketones 143 mediated by BX3.
Scheme 64: Lewis acid-promoted ring-opening reaction of 2,2-difluorocyclopropanecarbonyl chloride (148).
Scheme 65: Ring-opening reaction of the gem-difluorocyclopropyl ketone 106 by methanolic KOH.
Scheme 66: Hydrogenolysis of 1,1-difluoro-3-methyl-2-phenylcyclopropane (151).
Scheme 67: Synthesis of monofluoroalkenes 157.
Scheme 68: The stereoselective Ag-catalyzed defluorinative ring-opening diarylation of 1-trimethylsiloxy-2,2-d...
Scheme 69: Synthesis of 2-fluorinated allylic compounds 162.
Scheme 70: Pd-catalyzed cross-coupling reactions of gem-difluorinated cyclopropanes 161.
Scheme 71: The (Z)-selective Pd-catalyzed ring-opening sulfonylation of 2-(2,2-difluorocyclopropyl)naphthalene...
Figure 1: Structures of zosuquidar hydrochloride and PF-06700841.
Scheme 72: Synthesis of methylene-gem-difluorocyclopropane analogs of nucleosides.
Figure 2: Anthracene-difluorocyclopropane hybrid derivatives.
Figure 3: Further examples of difluorcyclopropanes in modern drug discovery.
Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251
Graphical Abstract
Figure 1: Highly-substituted five-membered carbocycle in biologically significant natural products.
Figure 2: Natural product synthesis featuring the all-carbon [3 + 2] cycloaddition. (Quaternary carbon center...
Scheme 1: Representative natural product syntheses that feature the all-carbon [3 + 2] cyclization as the key...
Scheme 2: (A) An intramolecular trimethylenemethane diyl [3 + 2] cycloaddition with allenyl diazo compound 38...
Scheme 3: (A) Palladium-catalyzed intermolecular carboxylative TMM cycloaddition [36]. (B) The proposed mechanism....
Scheme 4: Natural product syntheses that make use of palladium-catalyzed intermolecular [3 + 2] cycloaddition...
Scheme 5: (A) Phosphine-catalyzed [3 + 2] cycloaddition [17]. (B) The proposed mechanism.
Scheme 6: Lu’s [3 + 2] cycloaddition in natural product synthesis. (A) Synthesis of longeracinphyllin A (10) [41]...
Scheme 7: (A) Phosphine-catalyzed [3 + 2] annulation of unsymmetric isoindigo 100 with allene in the preparat...
Scheme 8: (A) Rhodium-catalyzed intracmolecular [3 + 2] cycloaddition [49]. (B) The proposed catalytic cycle of t...
Scheme 9: Total synthesis of natural products reported by Yang and co-workers applying rhodium-catalyzed intr...
Scheme 10: (A) Platinum(II)-catalyzed intermolecular [3 + 2] cycloaddition of propargyl ether 139 and n-butyl ...
Scheme 11: (A) Platinum-catalyzed intramolecular [3 + 2] cycloaddition of propargylic ketal derivative 142 to ...
Scheme 12: (A) Synthesis of phyllocladanol (21) features a Lewis acid-catalyzed formal intramolecular [3 + 2] ...
Scheme 13: The recent advances of [3 + 2] annulation in natural product synthesis. (A) The preparation of melo...
Beilstein J. Org. Chem. 2020, 16, 1418–1435, doi:10.3762/bjoc.16.118
Graphical Abstract
Scheme 1: [3 + 2] cyclization catalyzed by diaryl disulfide.
Scheme 2: [3 + 2] cycloaddition catalyzed by disulfide.
Scheme 3: Disulfide-bridged peptide-catalyzed enantioselective cycloaddition.
Scheme 4: Disulfide-catalyzed [3 + 2] methylenecyclopentane annulations.
Scheme 5: Disulfide as a HAT cocatalyst in the [4 + 2] cycloaddition reaction.
Scheme 6: Proposed mechanism of the [4 + 2] cycloaddition reaction using disulfide as a HAT cocatalyst.
Scheme 7: Disulfide-catalyzed ring expansion of vinyl spiro epoxides.
Scheme 8: Disulfide-catalyzed aerobic oxidation of diarylacetylene.
Scheme 9: Disulfide-catalyzed aerobic photooxidative cleavage of olefins.
Scheme 10: Disulfide-catalyzed aerobic oxidation of 1,3-dicarbonyl compounds.
Scheme 11: Proposed mechanism of the disulfide-catalyzed aerobic oxidation of 1,3-dicarbonyl compounds.
Scheme 12: Disulfide-catalyzed oxidation of allyl alcohols.
Scheme 13: Disulfide-catalyzed diboration of alkynes.
Scheme 14: Dehalogenative radical cyclization catalyzed by disulfide.
Scheme 15: Hydrodifluoroacetamidation of alkenes catalyzed by disulfide.
Scheme 16: Plausible mechanism of the hydrodifluoroacetamidation of alkenes catalyzed by disulfide.
Scheme 17: Disulfide-cocatalyzed anti-Markovnikov olefin hydration reactions.
Scheme 18: Disulfide-catalyzed decarboxylation of carboxylic acids.
Scheme 19: Proposed mechanism of the disulfide-catalyzed decarboxylation of carboxylic acids.
Scheme 20: Disulfide-catalyzed decarboxylation of carboxylic acids.
Scheme 21: Disulfide-catalyzed conversion of maleate esters to fumarates and 5H-furanones.
Scheme 22: Disulfide-catalyzed isomerization of difluorotriethylsilylethylene.
Scheme 23: Disulfide-catalyzed isomerization of allyl alcohols to carbonyl compounds.
Scheme 24: Proposed mechanism for the disulfide-catalyzed isomerization of allyl alcohols to carbonyl compound...
Scheme 25: Diphenyl disulfide-catalyzed enantioselective synthesis of ophirin B.
Scheme 26: Disulfide-catalyzed isomerization in the total synthesis of (+)-hitachimycin.
Scheme 27: Disulfide-catalyzed isomerization in the synthesis of (−)-gloeosporone.
Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107
Graphical Abstract
Figure 1: Imine-N-oxyl radicals (IV) discussed in the present review and other classes of N-oxyl radicals (I–...
Figure 2: The products of decomposition of iminoxyl radicals generated from oximes by oxidation with Ag2O.
Scheme 1: Generation of oxime radicals and study of the kinetics of their decay by photolysis of the solution...
Scheme 2: Synthesis of di-tert-butyliminoxyl radical and its decomposition products.
Scheme 3: The proposed reaction pathway of the decomposition of di-tert-butyliminoxyl radical (experimentally...
Scheme 4: Monomolecular decomposition of the tert-butyl(triethylmethyl)oxime radical.
Scheme 5: The synthesis and stability of the most stable dialkyl oxime radicals – di-tert-butyliminoxyl and d...
Scheme 6: The formation of iminoxyl radicals from β-diketones under the action of NO2.
Scheme 7: Synthesis of the diacetyliminoxyl radical.
Scheme 8: Examples of long-living oxime radicals with electron-withdrawing groups and the conditions for thei...
Figure 3: The electronic structure iminoxyl radicals and their geometry compared to the corresponding oximes.
Figure 4: Bond dissociation enthalpies (kcal/mol) of oximes and N,N-disubstituted hydroxylamines calculated o...
Scheme 9: Examples demonstrating the low reactivity of the di-tert-butyliminoxyl radical towards the substrat...
Scheme 10: The reactions of di-tert-butyliminoxyl radical with unsaturated hydrocarbons involving hydrogen ato...
Scheme 11: Possible mechanisms of reaction of di-tert-butyliminoxyl radical with alkenes.
Scheme 12: Products of the reaction between di-tert-butyliminoxyl radical and phenol derivatives.
Scheme 13: The reaction of di-tert-butyliminoxyl radical with amines.
Scheme 14: Reaction of di-tert-butyliminoxyl radicals with organolithium reagents.
Scheme 15: Cross-dehydrogenative C–O coupling of 1,3-dicarbonyl compounds with oximes under the action of mang...
Scheme 16: Cross-dehydrogenative C–O coupling of 1,3-dicarbonyl compounds with oximes under the action of Cu(BF...
Scheme 17: Oxidative C–O coupling of benzylmalononitrile (47) with 3-(hydroxyimino)pentane-2,4-dione (19).
Scheme 18: The proposed mechanism of the oxidative coupling of benzylmalononitrile (47) with diacetyl oxime (19...
Scheme 19: Oxidative C–O coupling of pyrazolones with oximes under the action of Fe(ClO4)3.
Scheme 20: The reaction of diacetyliminoxyl radical with pyrazolones.
Scheme 21: Oxidative C–O coupling of oximes with acetonitrile, ketones, and esters.
Scheme 22: Intramolecular cyclizations of oxime radicals to form substituted isoxazolines or cyclic nitrones.
Scheme 23: TEMPO-mediated oxidative cyclization of oximes with C–H bond cleavage.
Scheme 24: Proposed reaction mechanism of oxidative cyclization of oximes with C–H bond cleavage.
Scheme 25: Selectfluor/Bu4NI-mediated C–H oxidative cyclization of oximes.
Scheme 26: Oxidative cyclization of N-benzyl amidoximes to 1,2,4-oxadiazoles.
Scheme 27: The formation of quinazolinone 73a from 5-phenyl-4,5-dihydro-1,2,4-oxadiazole 74 under air.
Scheme 28: DDQ-mediated oxidative cyclization of thiohydroximic acids.
Scheme 29: Plausible mechanism of the oxidative cyclization of thiohydroximic acids.
Scheme 30: Silver-mediated oxidative cyclization of α-halogenated ketoximes and 1,3-dicarbonyl compounds.
Scheme 31: Possible pathway of one-pot oxidative cyclization of α-halogenated ketoximes and 1,3-dicarbonyl com...
Scheme 32: T(p-F)PPT-catalyzed oxidative cyclization of oximes with the formation of 1,2,4-oxadiazolines.
Scheme 33: Intramolecular cyclization of iminoxyl radicals involving multiple C=C and N=N bonds.
Scheme 34: Oxidative cyclization of β,γ- and γ,δ-unsaturated oximes employing the DEAD or TEMPO/DEAD system wi...
Scheme 35: Cobalt-catalyzed aerobic oxidative cyclization of β,γ-unsaturated oximes.
Scheme 36: Manganese-catalyzed aerobic oxidative cyclization of β,γ-unsaturated oximes.
Scheme 37: Visible light photocatalytic oxidative cyclization of β,γ-unsaturated oximes.
Scheme 38: TBAI/TBHP-mediated radical cascade cyclization of the β,γ-unsaturated oximes.
Scheme 39: TBAI/TBHP-mediated radical cascade cyclization of vinyl isocyanides with β,γ-unsaturated oximes.
Scheme 40: tert-Butylnitrite-mediated oxidative cyclization of unsaturated oximes with the introduction of an ...
Scheme 41: Transformation of unsaturated oxime to oxyiminomethylisoxazoline via the confirmed dimeric nitroso ...
Scheme 42: tert-Butylnitrite-mediated oxidative cyclization of unsaturated oximes with the introduction of a n...
Scheme 43: Synthesis of cyano-substituted oxazolines from unsaturated oximes using the TBN/[RuCl2(p-cymene)]2 ...
Scheme 44: Synthesis of trifluoromethylthiolated isoxazolines from unsaturated oximes.
Scheme 45: Copper-сatalyzed oxidative cyclization of β,γ-unsaturated oximes with the introduction of an azido ...
Scheme 46: TBHP-mediated oxidative cascade cyclization of β,γ-unsaturated oximes and unsaturated N-arylamides.
Scheme 47: Copper-сatalyzed oxidative cyclization of unsaturated oximes with the introduction of an amino grou...
Scheme 48: TEMPO-mediated oxidative cyclization of unsaturated oximes followed by elimination.
Scheme 49: Oxidative cyclization of β,γ-unsaturated oximes with the introduction of a trifluoromethyl group.
Scheme 50: Oxidative cyclization of unsaturated oximes with the introduction of a nitrile group.
Scheme 51: Oxidative cyclization of β,γ-unsaturated oximes to isoxazolines with the introduction of a nitrile ...
Scheme 52: Oxidative cyclization of β,γ-unsaturated oximes to isoxazolines with the introduction of a sulfonyl...
Scheme 53: Oxidative cyclization of β,γ- and γ,δ-unsaturated oximes to isoxazolines with the introduction of a...
Scheme 54: Oxidative cyclization of β,γ-unsaturated oximes to isoxazolines with the introduction of a thiocyan...
Scheme 55: PhI(OAc)2-mediated oxidative cyclization of oximes with C–S and C–Se bond formation.
Scheme 56: PhI(OAc)2-mediated oxidative cyclization of unsaturated oximes accompanied by alkoxylation.
Scheme 57: PhI(OAc)2-mediated cyclization of unsaturated oximes to methylisoxazolines.
Scheme 58: Oxidative cyclization-alkynylation of unsaturated oximes.
Scheme 59: TEMPO-mediated oxidative cyclization of C-glycoside ketoximes to C-glycosylmethylisoxazoles.
Scheme 60: Silver-сatalyzed oxidative cyclization of β,γ-unsaturated oximes with formation of fluoroalkyl isox...
Scheme 61: Oxidative cyclization of β,γ-unsaturated oximes with the formation of haloalkyl isoxazolines.
Scheme 62: Cyclization of β,γ-unsaturated oximes into haloalkyl isoxazolines under the action of the halogenat...
Scheme 63: Synthesis of haloalkyl isoxazoles and cyclic nitrones via oxidative cyclization and 1,2-halogen shi...
Scheme 64: Electrochemical oxidative cyclization of diaryl oximes.
Scheme 65: Copper-сatalyzed cyclization and dioxygenation oximes containing a triple C≡C bond.
Scheme 66: Photoredox-catalyzed sulfonylation of β,γ-unsaturated oximes by sulfonyl hydrazides.
Scheme 67: Oxidative cyclization of β,γ-unsaturated oximes with introduction of sulfonate group.
Scheme 68: Ultrasound-promoted oxidative cyclization of β,γ-unsaturated oximes.
Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103
Graphical Abstract
Figure 1: Selected examples of organic dyes. Mes-Acr+: 9-mesityl-10-methylacridinium, DCA: 9,10-dicyanoanthra...
Scheme 1: Activation modes in photocatalysis.
Scheme 2: Main strategies for the formation of C(sp3) radicals used in organophotocatalysis.
Scheme 3: Illustrative example for the photocatalytic oxidative generation of radicals from carboxylic acids:...
Scheme 4: Illustrative example for the photocatalytic reductive generation of C(sp3) radicals from redoxactiv...
Figure 2: Common substrates for the photocatalytic oxidative generation of C(sp3) radicals.
Scheme 5: Illustrative example for the photocatalytic oxidative generation of radicals from dihydropyridines ...
Scheme 6: Illustrative example for the photocatalytic oxidative generation of C(sp3) radicals from trifluorob...
Scheme 7: Illustrative example for the photocatalytic reductive generation of C(sp3) radicals from benzylic h...
Scheme 8: Illustrative example for the photocatalytic generation of C(sp3) radicals via direct HAT: the cross...
Scheme 9: Illustrative example for the photocatalytic generation of C(sp3) radicals via indirect HAT: the deu...
Scheme 10: Selected precursors for the generation of aryl radicals using organophotocatalysis.
Scheme 11: Illustrative example for the photocatalytic reductive generation of aryl radicals from aryl diazoni...
Scheme 12: Illustrative examples for the photocatalytic reductive generation of aryl radicals from haloarenes:...
Scheme 13: Illustrative example for the photocatalytic reductive generation of aryl radicals from aryl halides...
Scheme 14: Illustrative example for the photocatalytic reductive generation of aryl radicals from arylsulfonyl...
Scheme 15: Illustrative example for the reductive photocatalytic generation of aryl radicals from triaryl sulf...
Scheme 16: Main strategies towards acyl radicals used in organophotocatalysis.
Scheme 17: Illustrative example for the decarboxylative photocatalytic generation of acyl radicals from α-keto...
Scheme 18: Illustrative example for the oxidative photocatalytic generation of acyl radicals from acyl silanes...
Scheme 19: Illustrative example for the oxidative photocatalytic generation of carbamoyl radicals from 4-carba...
Scheme 20: Illustrative example of the photocatalytic HAT approach for the generation of acyl radicals from al...
Scheme 21: General reactivity of a) radical cations; b) radical anions; c) the main strategies towards aryl an...
Scheme 22: Illustrative example for the oxidative photocatalytic generation of alkene radical cations from alk...
Scheme 23: Illustrative example for the reductive photocatalytic generation of an alkene radical anion from al...
Figure 3: Structure of C–X radical anions and their neutral derivatives.
Scheme 24: Illustrative example for the photocatalytic reduction of imines and the generation of an α-amino C(...
Scheme 25: Illustrative example for the oxidative photocatalytic generation of aryl radical cations from arene...
Scheme 26: NCR classifications and generation.
Scheme 27: Illustrative example for the photocatalytic reductive generation of iminyl radicals from O-aryl oxi...
Scheme 28: Illustrative example for the photocatalytic oxidative generation of iminyl radicals from α-N-oxy ac...
Scheme 29: Illustrative example for the photocatalytic oxidative generation of iminyl radicals via an N–H bond...
Scheme 30: Illustrative example for the photocatalytic oxidative generation of amidyl radicals from Weinreb am...
Scheme 31: Illustrative example for the photocatalytic reductive generation of amidyl radicals from hydroxylam...
Scheme 32: Illustrative example for the photocatalytic reductive generation of amidyl radicals from N-aminopyr...
Scheme 33: Illustrative example for the photocatalytic oxidative generation of amidyl radicals from α-amido-ox...
Scheme 34: Illustrative example for the photocatalytic oxidative generation of aminium radicals: the N-aryltet...
Scheme 35: Illustrative example for the photocatalytic oxidative generation of nitrogen-centered radical catio...
Scheme 36: Illustrative example for the photocatalytic oxidative generation of nitrogen-centered radical catio...
Scheme 37: Illustrative example for the photocatalytic oxidative generation of hydrazonyl radical from hydrazo...
Scheme 38: Generation of O-radicals.
Scheme 39: Illustrative examples for the photocatalytic generation of O-radicals from N-alkoxypyridinium salts...
Scheme 40: Illustrative examples for the photocatalytic generation of O-radicals from alkyl hydroperoxides: th...
Scheme 41: Illustrative example for the oxidative photocatalytic generation of thiyl radicals from thiols: the...
Scheme 42: Main strategies and reagents for the generation of sulfonyl radicals used in organophotocatalysis.
Scheme 43: Illustrative example for the reductive photocatalytic generation of sulfonyl radicals from arylsulf...
Scheme 44: Illustrative example of a Cl atom abstraction strategy for the photocatalytic generation of sulfamo...
Scheme 45: Illustrative example for the oxidative photocatalytic generation of sulfonyl radicals from sulfinic...
Scheme 46: Illustrative example for the photocatalytic generation of electronically excited triplet states: th...
Scheme 47: Illustrative example for the photocatalytic generation of electronically excited triplet states: th...
Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76
Graphical Abstract
Scheme 1: Norrish type I and II dissociations.
Scheme 2: Proposed radical pair formation after the photolysis of benzaldehyde (8).
Scheme 3: Aldehydes in the Paterno–Büchi reaction.
Scheme 4: 2,3-Diazabicyclo[2.2.1]hept-2-ene (DBH).
Scheme 5: Dissociation pathways of benzaldehyde.
Scheme 6: Reactions that lead to polarized products detectable by CIDNP.
Scheme 7: MMA (26), DEABP (27), and Michler’s ketone (28).
Scheme 8: Radical intermediates of DEABP.
Scheme 9: Photoinitiated polymerization of monomeric MMA (26) using the quinoxalines 32 and benzaldehyde (8).
Scheme 10: Acetone (4) and formaldehyde (35) as photografting initiators.
Scheme 11: Photografting by employing acetaldehyde (36) as the photoinitiator.
Scheme 12: Proposed photolysis mechanism for aliphatic ketones 44 and formaldehyde (35).
Scheme 13: Initiator 50, reductant 51, and benzaldehyde derivatives 52–54 for the polymerization of the methac...
Scheme 14: Proposed mechanism of the photomediated atom transfer radical polymerization employing the benzalde...
Scheme 15: cis/trans isomerization employing triplet states of photosensitizers.
Scheme 16: Salicylaldehyde (68) forms an internal hydrogen bond.
Scheme 17: Olefin isomerization via energy transfer from a carbonyl compound.
Scheme 18: Mechanistic pathways for the Paterno–Büchi reaction.
Scheme 19: Isomeric oxetanes formed after photochemical addition of aryl aldehydes to 2-butenes.
Scheme 20: Rotation of the C3–C4 bond of the biradical intermediate may lead to all four conformations.
Scheme 21: Photolysis products of benzaldehyde (8) in different solvents. a) In benzene or ethanol. b) In hex-...
Scheme 22: N-tert-Butylbenzamide formation proceeds via a benzoyl radical.
Scheme 23: Photochemical pinacol coupling.
Scheme 24: Photochemical ATRA catalyzed by 4-anisaldehyde (52).
Scheme 25: Proposed triplet sensitization mechanism of the ATRA reaction in the presence of 4-anisaldehyde (52...
Scheme 26: Benzaldehyde-mediated photoredox CDC reaction: compatible amides and ethers.
Scheme 27: Photoredox cross-dehydrogenative coupling (CDC) conditions and proposed reaction mechanism.
Scheme 28: Optimized conditions for the photoredox merger reaction.
Scheme 29: Proposed mechanism for the C(sp3)–H alkylation/arylation of ethers.
Scheme 30: Substrate scope for the photochemical alkylation of ethers.
Scheme 31: C(sp3)–H Functionalization of N-containing molecules.
Scheme 32: Substrate scope for the photochemical alkylation of N-containing molecules.
Scheme 33: Additional products yielded by the photochemical alkylation reaction of N-containing molecules.
Scheme 34: C(sp3)–H functionalization of thioethers.
Scheme 35: Proposed mechanism for the C(sp3)–H alkylation/arylation of N-containing molecules and thioethers.
Scheme 36: Hydroacylation using 4-cyanobenzaldehyde (53) as the photoinitiator.
Scheme 37: Selectivity for the formation of the α,α-disubstituted aldehydes.
Scheme 38: Substrate scope for the photochemical addition of aldehydes to Michael acceptors.
Scheme 39: Proposed mechanism for the hydroacylation of Michael acceptors using 4-cyanobenzaldehyde (53) as th...
Scheme 40: Catalytic arylation of aromatic aldehydes by aryl bromides in which the reaction product acts as th...
Scheme 41: Proposed mechanism for the catalytic arylation of benzaldehydes by aryl bromides in which the react...
Scheme 42: Functionalization of the chiral cyclobutanes 180.
Scheme 43: Optimized reaction conditions and proposed mechanism for the sulfonylcyanation of cyclobutenes.
Beilstein J. Org. Chem. 2020, 16, 384–390, doi:10.3762/bjoc.16.36
Graphical Abstract
Scheme 1: A high yielding, highly selective room-temperature direct arylation reaction between indole and iod...
Figure 1: 1H NMR (500 MHz, CDCl3) of (a) 5-iodo-1-octylindole monomer (b) PIn prepared according to condition...
Figure 2: MALDI–TOF MS of PIn, indicating octylindole repeat units with three different types of end groups. ...
Scheme 2: Commonly discussed mechanisms for C2 selective direct arylation, none containing radical intermedia...
Scheme 3: Proposed mechanism for palladium radical involved reaction between indole and iodobenzene.
Scheme 4: Radical trap effects on literature methods for the direct arylation at room temperature. A) From re...
Beilstein J. Org. Chem. 2020, 16, 248–280, doi:10.3762/bjoc.16.26
Graphical Abstract
Figure 1: List of photoredox catalysts used for C–H bond functionalizations.
Figure 2: List of metal-based photoredox catalysts used in this review article.
Figure 3: Jablonski diagram.
Figure 4: Photoredox catalysis via reductive or oxidative pathways. D = donor, A = acceptor, S = substrate, P...
Figure 5: Schematic representation of the combination of photoredox catalysis and transition metal catalysis.
Scheme 1: Weinreb amide C–H olefination.
Figure 6: Mechanism for the formation of 21 from 19 using photoredox catalyst 11.
Scheme 2: C–H olefination of phenolic ethers.
Scheme 3: Decarboxylative acylation of acetanilides.
Figure 7: Mechanism for the formation of 30 from acetanilide derivatives.
Scheme 4: Synthesis of fluorenone derivatives by intramolecular deoxygenative acylation of biaryl carboxylic ...
Figure 8: Mechanism for the photoredox-catalyzed synthesis of fluorenone derivatives.
Scheme 5: Synthesis of benzothiazoles via aerobic C–H thiolation.
Figure 9: Plausible mechanism for the construction of benzothiazoles from benzothioamides.
Scheme 6: Synthesis of benzothiazoles via oxidant-free C–H thiolation.
Figure 10: Mechanism involved in the synthesis of benzothiazoles via oxidant-free C–H thiolation.
Scheme 7: Synthesis of indoles via C–H cyclization of anilides with alkynes.
Scheme 8: Preparation of 3-trifluoromethylcoumarins via C–H cyclization of arylpropiolate esters.
Figure 11: Mechanistic pathway for the synthesis of coumarin derivatives via C–H cyclization.
Scheme 9: Monobenzoyloxylation without chelation assistance.
Figure 12: Plausible mechanism for the formation of 71 from 70.
Scheme 10: Aryl-substituted arenes prepared by inorganic photoredox catalysis using 12a.
Figure 13: Proposed mechanism for C–H arylations in the presence of 12a and a Pd catalyst.
Scheme 11: Arylation of purines via dual photoredox catalysis.
Scheme 12: Arylation of substituted arenes with an organic photoredox catalyst.
Scheme 13: C–H trifluoromethylation.
Figure 14: Proposed mechanism for the trifluoromethylation of 88.
Scheme 14: Synthesis of benzo-3,4-coumarin derivatives.
Figure 15: Plausible mechanism for the synthesis of substituted coumarins.
Scheme 15: Oxidant-free oxidative phosphonylation.
Figure 16: Mechanism proposed for the phosphonylation reaction of 100.
Scheme 16: Nitration of anilines.
Figure 17: Plausible mechanism for the nitration of aniline derivatives via photoredox catalysis.
Scheme 17: Synthesis of carbazoles via intramolecular amination.
Figure 18: Proposed mechanism for the formation of carbazoles from biaryl derivatives.
Scheme 18: Synthesis of substituted phenols using QuCN.
Figure 19: Mechanism for the synthesis of phenol derivatives with photoredox catalyst 8.
Scheme 19: Synthesis of substituted phenols with DDQ (5).
Figure 20: Possible mechanism for the generation of phenols with the aid of photoredox catalyst 5.
Scheme 20: Aerobic bromination of arenes using an acridinium-based photocatalyst.
Scheme 21: Aerobic bromination of arenes with anthraquinone.
Figure 21: Proposed mechanism for the synthesis of monobrominated compounds.
Scheme 22: Chlorination of benzene derivatives with Mes-Acr-MeClO4 (2).
Figure 22: Mechanism for the synthesis of 131 from 132.
Scheme 23: Chlorination of arenes with 4CzIPN (5a).
Figure 23: Plausible mechanism for the oxidative photocatalytic monochlorination using 5a.
Scheme 24: Monofluorination using QuCN-ClO4 (8).
Scheme 25: Fluorination with fluorine-18.
Scheme 26: Aerobic amination with acridinium catalyst 3a.
Figure 24: Plausible mechanism for the aerobic amination using acridinium catalyst 3a.
Scheme 27: Aerobic aminations with semiconductor photoredox catalyst 18.
Scheme 28: Perfluoroalkylation of arenes.
Scheme 29: Synthesis of benzonitriles in the presence of 3a.
Figure 25: Plausible mechanism for the synthesis of substituted benzonitrile derivatives in the presence of 3a....
Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264
Graphical Abstract
Figure 1: General classification of asymmetric electroorganic reactions.
Scheme 1: Asymmetric reduction of 4-acetylpyridine using a modified graphite cathode.
Scheme 2: Asymmetric hydrogenation of ketones using Raney nickel powder electrodes modified with optically ac...
Scheme 3: Asymmetric reduction of prochiral activated olefins with a poly-ʟ-valine-coated graphite cathode.
Scheme 4: Asymmetric reduction of prochiral carbonyl compounds, oximes and gem-dibromides on a poly-ʟ-valine-...
Scheme 5: Asymmetric hydrogenation of prochiral ketones with poly[RuIII(L)2Cl2]+-modified carbon felt cathode...
Scheme 6: Asymmetric hydrogenation of α-keto esters using chiral polypyrrole film-coated cathode incorporated...
Scheme 7: Quinidine and cinchonidine alkaloid-induced asymmetric electroreduction of acetophenone.
Scheme 8: Asymmetric electroreduction of 4- and 2-acetylpyridines at a mercury cathode in the presence of a c...
Scheme 9: Enantioselective reduction of 4-methylcoumarin in the presence of catalytic yohimbine.
Scheme 10: Cinchonine-induced asymmetric electrocarboxylation of 4-methylpropiophenone.
Scheme 11: Enantioselective hydrogenation of methyl benzoylformate using an alkaloid entrapped silver cathode.
Scheme 12: Alkaloid-induced enantioselective hydrogenation using a Cu nanoparticle cathode.
Scheme 13: Alkaloid-induced enantioselective hydrogenation of aromatic ketones using a bimetallic Pt@Cu cathod...
Scheme 14: Enantioselective reduction of ketones at mercury cathode using N,N'-dimethylquininium tetrafluorobo...
Scheme 15: Asymmetric synthesis of an amino acid using an electrode modified with amino acid oxidase and elect...
Scheme 16: Asymmetric oxidation of p-tolyl methyl sulfide using chemically modified graphite anode.
Scheme 17: Asymmetric oxidation of unsymmetric sulfides using poly(amino acid)-coated electrodes.
Scheme 18: Enantioselective, electocatalytic oxidative coupling on TEMPO-modified graphite felt electrode in t...
Scheme 19: Asymmetric electrocatalytic oxidation of racemic alcohols on a TEMPO-modified graphite felt electro...
Scheme 20: Asymmetric electrocatalytic lactonization of diols on TEMPO-modified graphite felt electrodes.
Scheme 21: Asymmetric electrochemical pinacolization in a chiral solvent.
Scheme 22: Asymmetric electroreduction using a chiral supporting electrolyte.
Scheme 23: Asymmetric anodic oxidation of enol acetates using chiral supporting electrolytes.
Scheme 24: Kinetic resolution of primary amines using a chiral N-oxyl radical mediator.
Scheme 25: Chiral N-oxyl-radical-mediated kinetic resolution of secondary alcohols via electrochemical oxidati...
Scheme 26: Chiral iodoarene-mediated asymmetric electrochemical lactonization.
Scheme 27: Os-catalyzed electrochemical asymmetric dihydroxylation of olefins using the Sharpless ligand and i...
Scheme 28: Asymmetric electrochemical epoxidation of olefins catalyzed by a chiral Mn-salen complex.
Scheme 29: Asymmetric electrooxidation of 1,2-diols, and amino alcohols using a chiral copper catalyst.
Scheme 30: Mechanism of asymmetric electrooxidation of 1,2-diols, and amino alcohols using a chiral copper cat...
Scheme 31: Enantioselective electrocarboxylation catalyzed by an electrogenerated chiral [CoI(salen)]− complex....
Scheme 32: Asymmetric oxidative cross coupling of 2-acylimidazoles with silyl enol ethers.
Scheme 33: Ni-catalyzed asymmetric electroreductive cleavage of allylic β-keto ester 89.
Scheme 34: Asymmetric alkylation using a combination of electrosynthesis and a chiral Ni catalyst.
Scheme 35: Mechanism of asymmetric alkylation using a combination of electrosynthesis and a chiral Ni catalyst....
Scheme 36: Asymmetric epoxidation by electrogenerated percarbonate and persulfate ions in the presence of chir...
Scheme 37: α-Oxyamination of aldehydes via anodic oxidation catalyzed by chiral secondary amines.
Scheme 38: The α-alkylation of aldehydes via anodic oxidation catalyzed by chiral secondary amines.
Scheme 39: Mechanism of α-alkylation of aldehydes via anodic oxidation catalyzed by chiral secondary amines.
Scheme 40: Electrochemical chiral secondary amine-catalyzed intermolecular α-arylation of aldehydes.
Scheme 41: Mechanism of electrochemical chiral secondary amine-catalyzed intermolecular α-arylation of aldehyd...
Scheme 42: Asymmetric cross-dehydrogenative coupling of tertiary amines with simple ketones via an electrochem...
Scheme 43: Electroenzymatic asymmetric reduction using enoate reductase.
Scheme 44: Assymetric reduction using alcohol dehydrogenase as the electrocatalyst.
Scheme 45: Asymmetric electroreduction catalyzed by thermophilic NAD-dependent alcohol dehydrogenase.
Scheme 46: Asymmetric epoxidation of styrene by electrochemical regeneration of flavin-dependent monooxygenase....
Scheme 47: Asymmetric electroreduction using a chloroperoxidase catalyst.
Scheme 48: Asymmetric electrochemical transformation mediated by hydrophobic vitamin B12.
Scheme 49: Diastereoselective cathodic reduction of phenylglyoxalic acids substituted with amines as chiral au...
Scheme 50: Ni-catalyzed asymmetric electroreductive cross coupling of aryl halides with α-chloropropanoic acid...
Scheme 51: Electrochemical Mannich addition of silyloxyfuran to in situ-generated N-acyliminium ions.
Scheme 52: Stereoselective electroreductive homodimerization of cinnamates attached to a camphor-derived chira...
Scheme 53: Diastereoselective electrochemical carboxylation of chiral α-bromocarboxylic acid derivatives.
Scheme 54: Electrocatalytic stereoselective conjugate addition of chiral β-dicarbonyl compounds to methyl viny...
Scheme 55: Stereoselective electrochemical carboxylation of chiral cinnamic acid derivatives under a CO2 atmos...
Scheme 56: Electrochemical diastereoselective α-alkylation of pyrrolidines attached with phosphorus-derived ch...
Scheme 57: Electrogenerated cyanomethyl anion-induced synthesis of chiral cis-β-lactams from amides bearing ch...
Scheme 58: Diastereoselective anodic oxidation followed by intramolecular cyclization of ω-hydroxyl amides bea...
Scheme 59: Electrochemical deprotonation of Ni(II) glycinate containing (S)-BPB as a chiral auxiliary: diaster...
Scheme 60: Enantioselective electroreductive coupling of diaryl ketones with α,β-unsaturated carbonyl compound...
Scheme 61: Asymmetric total synthesis of ropivacaine and its analogues using a electroorganic reaction as a ke...
Scheme 62: Asymmetric total synthesis of (−)-crispine A and its natural enantiomer via anodic cyanation of tet...
Scheme 63: Asymmetric oxidative electrodimerization of cinnamic acid derivatives as key step for the synthesis...