Search for "catalyst-free" in Full Text gives 81 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45
Graphical Abstract
Scheme 1: Features of the ideal reaction (redrawn from P. A. Wender et al. [1]).
Scheme 2: Some of the most popular MCRs with formaldehyde as the carbonyl component.
Scheme 3: Ugi reaction under a catalyzed electro-oxidation process using TEMPO (2,2,6,6-tetramethyl-1-piperid...
Scheme 4: Examples of different products obtained by MCRs in which DMSO serves as -SCH3 source.
Scheme 5: Mechanism of the decomposition of DMSO under acidic or thermal conditions. a) In situ generation of...
Scheme 6: Povarov multicomponent reaction to quinolines.
Scheme 7: Example of the Povarov reaction with formaldehyde with a julolidine derivative as main product.
Scheme 8: Povarov multicomponent reaction to quinoline derivatives I and II using DMSO as formaldehyde surrog...
Scheme 9: Example of a Povarov three-component reaction with change of catalyst, yielding regioisomer III. In...
Scheme 10: The Povarov three-component reactions carried out under acidic catalysis to afford quinoline regios...
Scheme 11: Different MCR routes involving DMSO to synthesize complex heterocycles such as diarylpyridines and ...
Scheme 12: Pyrazole synthesis by a three-component reaction using DMSO as a source of a C-1 unit.
Scheme 13: Three-component reactions for the synthesis of aliphatic heterocycles 13 and 14 using DMSO as a for...
Scheme 14: Proposed mechanism for the 3CR between homoallylic amines, disulfides, and DMSO.
Scheme 15: Mannich-type reaction using DMSO as formaldehyde surrogate.
Scheme 16: Mechanism for the 3CR-Mannich-type reaction between aryl ketone 18, saccharine (19), and DMSO. The ...
Scheme 17: Mannich-type reaction using DMSO as formaldehyde surrogate and under oxidative activation.
Scheme 18: Three-component reaction between an indazole, a carboxylic acid, and DMSO.
Scheme 19: Amine–aldehyde–alkyne (AAA) coupling reaction and plausible mechanism.
Scheme 20: AHA coupling for the synthesis of propargylamines using dihalomethanes as C1 building blocks.
Scheme 21: AHA coupling using CH2Cl2 as both solvent and methylene source.
Scheme 22: Examples of propargylamines synthesized under catalytic AHA protocols.
Scheme 23: Proposed mechanism for the synthesis of propargylamines using dichloromethane as a C1 source.
Scheme 24: Mechanism proposed for the generation of the aminal intermediate E by Buckley et al. [68].
Scheme 25: Pudovic and Kabachnik–Fields reactions for the synthesis of α-aminophosphonates.
Scheme 26: a) Abramov side reaction that generates α-hydroxy phosphonate as a byproduct during the Kabachnik-F...
Scheme 27: Catalyst-free three component reaction to afford α-amino phosphorus product 35 using 1,1-dihaloalka...
Scheme 28: a) Proposed mechanism for the three-component reaction of dichloromethane, amine and phosphorus com...
Scheme 29: Ugi-ammonia strategy using HMTA as a formaldehyde surrogate.
Scheme 30: Glyoxylate and its derivatives as C1 building blocks.
Scheme 31: The Groebke–Blackburn–Bienaymé multicomponent reaction (GBB) and its mechanism.
Scheme 32: a) Byproducts in the GBB multicomponent reaction (GBB) when formaldehyde is used as the carbonyl co...
Scheme 33: Possible regioisomers in the GBB multicomponent reaction when formaldehyde is used as the carbonyl ...
Scheme 34: The multicomponent GBB reaction yields 2-unsubstituted 3-aminoimidazo heterocycles 42a using MP-gly...
Scheme 35: GBB multicomponent reaction to 2-unsubstituted 3-amino imidazo heterocycles 42a using glyoxylic aci...
Scheme 36: GBB reaction using glyoxylic acid immobilized on silica as formaldehyde surrogate.
Scheme 37: Bioactive products synthesized by the GBB reaction using glyoxylic acid.
Scheme 38: van Leusen three-component reaction to imidazoles.
Scheme 39: Side reaction during the synthesis of imidazoles with formaldehyde as the carbonyl compound.
Scheme 40: Optimization of the van Leusen three component reaction to 1,4-disubstituted imidazoles 43 using gl...
Scheme 41: Application of the Sisko strategy [96] for the synthesis of CB1 receptor antagonist compounds [97].
Scheme 42: Side reaction, when NH4OH is used as amine component.
Scheme 43: Ugi-type adducts with the ester moiety and the acidic CH to be used for post-cyclization sequences.
Scheme 44: Ugi/cycloisomerization process to pyrrolones 51, butenolides 52, and pyrroline 53.
Scheme 45: Radical cyclization reactions from Ugi adducts promoted by TEMPO.
Scheme 46: Hydrolysis and decarboxylation reactions to products with incorporation of a C1 unit of ethyl glyox...
Scheme 47: One-step synthetic route to pyrrolones 60 using phenylglyoxal.
Scheme 48: Ugi-pseudo-Knoevenagel-pseudo-Dieckmann cascade sequence for the synthesis of fused heterocycles.
Scheme 49: Ugi-pseudo-Knoevenagel reaction from ethyl glyoxylate.
Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15
Graphical Abstract
Figure 1: Selected examples containing tricyclic imidazole, CF2H or PhCF2 group.
Scheme 1: Strategies for the synthesis of difluoromethylated and difluoroarylmethylated tricyclic imidazoles.
Scheme 2: Substrate scope of the protocol. Reaction conditions: 1 (0.2 mmol), 2 (1.4 mmol), and PIDA (0.8 mmo...
Scheme 3: Control experiments and plausible mechanism.
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, 2870–2882, doi:10.3762/bjoc.20.241
Graphical Abstract
Figure 1: Representation of distinguished structures of benzodiazepine/benzoxazepine/benzothiazepine with pha...
Scheme 1: Methods for the construction of pyrrole-fused heterocycles through I-MCR reactions.
Scheme 2: The model reaction of dibenzoxazepine, gem-diactivated olefin (2-benzylidenemalononitrile), and cyc...
Scheme 3: Substrate scope. Conditions: Reactions were carried out using 1 (0.55 mmol), 2 (0.55 mmol), and 3 (...
Scheme 4: Substrate scope..Conditions: reactions were carried out using 1 (0.55 mmol), 2 (0.55 mmol), and 5 (...
Figure 2: The crystal structure of 4h (CCDC 2365305).
Figure 3: The DNMR (dynamic nuclear magnetic resonance) spectra of compound 6f (DMSO-d6, 300 MHz) at 25–85 °C...
Figure 4: The crystal structure of 6a (CCDC2365306).
Scheme 5: A suggested mechanism for compounds 4.
Scheme 6: Synthesis of pyrrole-fused dibenzoxazepine/triazolobenzodiazepine through a 4-CR.
Scheme 7: Gram-scale synthesis of pyrrole-fused dibenzoxazepine/triazolobenzodiazepine 4a and 6a via 3-CRs.
Figure 5: UV–vis absorption for compounds 4a, 6c and QS (quinine sulfate) (a); emission for 4a, 6c and QS (b)...
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, 1713–1745, doi:10.3762/bjoc.20.152
Graphical Abstract
Figure 1: Steroidal spiro heterocycles with remarkable pharmacological activity.
Scheme 1: Synthesis of the spirooxetanone 2. a) t-BuOK, THF, rt, 16%.
Scheme 2: Synthesis of the 17-spirooxetane derivative 7. a) HC≡C(CH2)2CH2OTBDPS, n-BuLi, THF, BF3·Et2O, −78 °...
Scheme 3: Pd-catalyzed carbonylation of steroidal alkynols to produce α-methylene-β-lactones at C-3 and C-17 ...
Scheme 4: Catalyst-free protocol to obtain functionalized spiro-lactones by an intramolecular C–H insertion. ...
Scheme 5: One-pot procedure from dienamides to spiro-β-lactams. a) 1. Ac2O, DMAP, Et3N, CH2Cl2, 2. malononitr...
Scheme 6: Spiro-γ-lactone 20 afforded from 7α-alkanamidoestrone derivative 17. a) HC≡CCH2OTHP, n-BuLi, THF, –...
Scheme 7: Synthesis of the 17-spiro-γ-lactone 23, a key intermediate to obtain spironolactone. a) Ethyl propi...
Scheme 8: Synthetic pathway to obtain 17-spirodihydrofuran-3(2H)-ones from 17-oxosteroids. a) 1-Methoxypropa-...
Scheme 9: One-pot procedure to obtain 17-spiro-2H-furan-3-one compounds. a) NaH, diethyl oxalate, benzene, rt...
Scheme 10: Synthesis of 17-spiro-2H-furan-3-one derivatives. a) RCH=NOH, N-chlorosuccinimide/CHCl3, 99%; b) H2...
Scheme 11: Intramolecular condensation of a γ-acetoxy-β-ketoester to synthesize spirofuranone 37. a) (CH3CN)2P...
Scheme 12: Synthesis of spiro 2,5-dihydrofuran derivatives. a) Allyl bromide, DMF, NaH, 0 °C to rt, 93%; b) G-...
Scheme 13: First reported synthesis of C-16 dispiropyrrolidine derivatives. a) Sarcosine, isatin, MeOH, reflux...
Scheme 14: Cycloadducts 47 with antiproliferative activity against human cancer cell lines. a) 1,4-Dioxane–MeO...
Scheme 15: Spiropyrrolidine compounds generated from (E)-16-arylidene steroids and different ylides. a) Acenap...
Scheme 16: 3-Spiropyrrolidines 52a–c obtained from ketones 50a–c. a) p-Toluenesulfonyl hydrazide, MeOH, rt; b)...
Scheme 17: 16-Spiropyrazolines from 16-methylene-13α-estrone derivatives. a) AgOAc, toluene, rt, 78–81%.
Scheme 18: 6-Spiroimidazolines 57 synthesized by a one-pot multicomponent reaction. a) R3-NC, T3P®, DMSO, 70 °...
Scheme 19: Synthesis of spiro-1,3-oxazolines 60, tested as progesterone receptor antagonist agents. a) CF3COCF3...
Scheme 20: Synthesis of spiro-1,3-oxazolidin-2-ones 63 and 66a,b. a) RNH2, EtOH, 70 °C, 70–90%; b) (CCl3O)2CO,...
Scheme 21: Formation of spiro 1,3-oxazolidin-2-one and spiro 2-substituted amino-4,5-dihydro-1,3-oxazoles from ...
Scheme 22: Synthesis of diastereomeric spiroisoxazolines 74 and 75. a) Ar-C(Cl)=N-OH, DIPEA, toluene, rt, 74 (...
Scheme 23: Spiro 1,3-thiazolidine derivatives 77–79 obtained from 2α-bromo-5α-cholestan-3-one 76. a) 2-aminoet...
Scheme 24: Method for the preparation of derivative 83. a) Benzaldehyde, MeOH, reflux, 77%; b) thioglycolic ac...
Scheme 25: Synthesis of spiro 1,3-thiazolidin-4-one derivatives from steroidal ketones. a) Aniline, EtOH, refl...
Scheme 26: Synthesis of spiro N-aryl-1,3-thiazolidin-4-one derivatives 91 and 92. a) Sulfanilamide, DMF, reflu...
Scheme 27: 1,2,4-Trithiolane dimers 94a–e selectively obtained from carbonyl derivatives. a) LR, CH2Cl2, reflu...
Scheme 28: Spiro 1,2,4-triazolidin-3-ones synthesized from semicarbazones. a) H2O2, CHCl3, 0 °C, 82–85%.
Scheme 29: Steroidal spiro-1,3,4-oxadiazoline 99 obtained in two steps from cholest-5-en-3-one (97). a) NH2NHC...
Scheme 30: Synthesis of spiro-1,3,4-thiadiazoline 101 by cyclization and diacetylation of thiosemicarbazone 100...
Scheme 31: Mono- and bis(1,3,4-thiadiazolines) obtained from estrane and androstane derivatives. a) H2NCSNHNH2...
Scheme 32: Different reaction conditions to synthesize spiro-1,3,2-oxathiaphospholanes 108 and 109.
Scheme 33: Spiro-δ-lactones derived from ADT and epi-ADT as inhibitors of 17β-HSDs. a) CH≡C(CH2)2OTHP, n-BuLi,...
Scheme 34: Spiro-δ-lactams 123a,b obtained in a five-step reaction sequence. a) (R)-(+)-tert-butylsulfinamide,...
Scheme 35: Steroid-coumarin conjugates as fluorescent DHT analogues to study 17-oxidoreductases for androgen m...
Scheme 36: 17-Spiro estradiolmorpholinones 130 bearing two types of molecular diversity. a) ʟ- or ᴅ-amino acid...
Scheme 37: Steroidal spiromorpholinones as inhibitors of enzyme 17β-HSD3. a) Methyl ester of ʟ- or ᴅ-leucine, ...
Scheme 38: Steroidal spiro-morpholin-3-ones achieved by N-alkylation or N-acylation of amino diols 141, follow...
Scheme 39: Straightforward method to synthesize a spiromorpholinone derivative from estrone. a) BnBr, K2CO3, CH...
Scheme 40: Pyrazolo[4,3-e][1,2,4]-triazine derivatives 152–154. a) 4-Aminoantipyrine, EtOH/DMF, reflux, 82%; b...
Scheme 41: One-pot procedure to synthesize spiro-1,3,4-thiadiazine derivatives. a) NH2NHCSCONHR, H2SO4, dioxan...
Scheme 42: 1,2,4-Trioxanes with antimalarial activity. a) 1. O2, methylene blue, CH3CN, 500 W tungsten halogen...
Scheme 43: Tetraoxanes 167 and 168 synthesized from ketones 163, 165 and 166. a) NaOH, iPrOH/H2O, 80 °C, 93%; ...
Scheme 44: 1,2,4,5-Tetraoxanes bearing a steroidal moiety and a cycloalkane. a) 30% H2O2/CH2Cl2/CH3CN, HCl, rt...
Scheme 45: Spiro-1,3,2-dioxaphosphorinanes obtained from estrone derivatives. a) KBH4, MeOH, THF or CH2Cl2; b)...
Scheme 46: Synthesis of steroidal spiro-ε-lactone 183. a) 1. Jones reagent, acetone, 0 °C to rt, 2. ClCOCOCl, ...
Scheme 47: Synthesis of spiro-2,3,4,7-tetrahydrooxepines 185 and 187 derived from mestranol and lynestrenol (38...
Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116
Graphical Abstract
Scheme 1: Electrochemical hydroarylation of alkenes with aryl halides.
Scheme 2: Substrate scope. Reaction conditions for 1 (X = Cl, Br): 1 (1.0 mmol), 2 (3.5 mmol), 1,3-DCB (5 mol...
Scheme 3: Gram-scale reaction and control experiments.
Scheme 4: Plausible mechanism.
Beilstein J. Org. Chem. 2024, 20, 1292–1297, doi:10.3762/bjoc.20.112
Graphical Abstract
Scheme 1: Phenotellurazine-catalyzed cross-dehydrogenative couplings.
Scheme 2: Screening of new Te(II)-catalyst candidates. ODCB: ortho-dichlorobenzene.
Scheme 3: Phenotellurazine-catalyzed cross-dehydrogenative indole dimerization.
Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87
Graphical Abstract
Scheme 1: Pd(0)-catalyzed domino C,N-coupling/carbonylation/Suzuki coupling reaction for the synthesis of 2-a...
Scheme 2: Pd(0)-catalyzed single isonitrile insertion: synthesis of 1-(3-amino)-1H-indol-2-yl)-1-ketones.
Scheme 3: Pd(0)-catalyzed gas-free carbonylation of 2-alkynylanilines to 1-(1H-indol-1-yl)-2-arylethan-1-ones....
Scheme 4: Pd(II)-catalyzed heterocyclization/alkoxycarbonylation of 2-alkynylaniline imines.
Scheme 5: Pd(II)-catalyzed heterocyclization/alkoxycarbonylation of 2-alkynylanilines to N-substituted indole...
Scheme 6: Synthesis of indol-2-acetic esters by Pd(II)-catalyzed carbonylation of 1-(2-aminoaryl)-2-yn-1-ols.
Scheme 7: Pd(II)-catalyzed carbonylative double cyclization of suitably functionalized 2-alkynylanilines to 3...
Scheme 8: Indole synthesis by deoxygenation reactions of nitro compounds reported by Cenini et al. [21].
Scheme 9: Indole synthesis by reduction of nitro compounds: approach reported by Watanabe et al. [22].
Scheme 10: Indole synthesis from o-nitrostyrene compounds as reported by Söderberg and co-workers [23].
Scheme 11: Synthesis of fused indoles (top) and natural indoles present in two species of European Basidiomyce...
Scheme 12: Synthesis of 1,2-dihydro-4(3H)-carbazolones through N-heteroannulation of functionalized 2-nitrosty...
Scheme 13: Synthesis of indoles from o-nitrostyrenes by using Pd(OAc)2 and Pd(tfa)2 in conjunction with bident...
Scheme 14: Synthesis of substituted 3-alkoxyindoles via palladium-catalyzed reductive N-heteroannulation.
Scheme 15: Synthesis of 3-arylindoles by palladium-catalyzed C–H bond amination via reduction of nitroalkenes.
Scheme 16: Synthesis of 2,2′-bi-1H-indoles, 2,3′-bi-1H-indoles, 3,3′-bi-1H-indoles, indolo[3,2-b]indoles, indo...
Scheme 17: Pd-catalyzed reductive cyclization of 1,2-bis(2-nitrophenyl)ethene and 1,1-bis(2-nitrophenyl)ethene...
Scheme 18: Flow synthesis of 2-substituted indoles by reductive carbonylation.
Scheme 19: Pd-catalyzed synthesis of variously substituted 3H-indoles from nitrostyrenes by using Mo(CO)6 as C...
Scheme 20: Synthesis of indoles from substituted 2-nitrostyrenes (top) and ω-nitrostyrenes (bottom) via reduct...
Scheme 21: Synthesis of indoles from substituted 2-nitrostyrenes with formic acid as CO source.
Scheme 22: Ni-catalyzed carbonylative cyclization of 2-nitroalkynes and aryl iodides (top) and the Ni-catalyze...
Scheme 23: Mechanism of the Ni-catalyzed carbonylative cyclization of 2-nitroalkynes and aryl iodides (top) an...
Scheme 24: Route to indole derivatives through Rh-catalyzed benzannulation of heteroaryl propargylic esters fa...
Scheme 25: Pd-catalyzed cyclization of 2-(2-haloaryl)indoles reported by Yoo and co-workers [54], Guo and co-worke...
Scheme 26: Approach for the synthesis of 6H-isoindolo[2,1-a]indol-6-ones reported by Huang and co-workers [57].
Scheme 27: Zhou group’s method for the synthesis of 6H-isoindolo[2,1-a]indol-6-ones.
Scheme 28: Synthesis of 6H-isoindolo[2,1-a]indol-6-ones from o-1,2-dibromobenzene and indole derivatives by us...
Scheme 29: Pd(OAc)2-catalyzed Heck cyclization of 2-(2-bromophenyl)-1-alkyl-1H-indoles reported by Guo et al. [55]....
Scheme 30: Synthesis of indolo[1,2-a]quinoxalinone derivatives through Pd/Cu co-catalyzed carbonylative cycliz...
Scheme 31: Pd-catalyzed carbonylative cyclization of o-indolylarylamines and N-monosubstituted o-indolylarylam...
Scheme 32: Pd-catalyzed diasteroselective carbonylative cyclodearomatization of N-(2-bromobenzoyl)indoles with...
Scheme 33: Pd(0)-catalyzed synthesis of CO-linked heterocyclic scaffolds from alkene-indole derivatives and 2-...
Scheme 34: Proposed mechanism for the Pd(0)-catalyzed synthesis of CO-linked heterocyclic scaffolds.
Scheme 35: Pd-catalyzed C–H and N–H alkoxycarbonylation of indole derivatives to indole-3-carboxylates and ind...
Scheme 36: Rh-catalyzed C–H alcoxycarbonylation of indole derivatives to indole-3-carboxylates reported by Li ...
Scheme 37: Pd-catalyzed C–H alkoxycarbonylation of indole derivatives with alcohols and phenols to indole-3-ca...
Scheme 38: Synthesis of N-methylindole-3-carboxylates from N-methylindoles and phenols through metal-catalyst-...
Scheme 39: Synthesis of indol-3-α-ketoamides (top) and indol-3-amides (bottom) via direct double- and monoamin...
Scheme 40: The direct Sonogashira carbonylation coupling reaction of indoles and alkynes via Pd/CuI catalysis ...
Scheme 41: Synthesis of indole-3-yl aryl ketones reported by Zhao and co-workers [73] (path a) and Zhang and co-wo...
Scheme 42: Pd-catalyzed carbonylative synthesis of BIMs from aryl iodides and N-substituted and NH-free indole...
Scheme 43: Cu-catalyzed direct double-carbonylation and monocarbonylation of indoles and alcohols with hexaket...
Scheme 44: Rh-catalyzed direct C–H alkoxycarbonylation of indoles to indole-2-carboxylates [79] (top) and Co-catal...
Scheme 45: Pd-catalyzed carbonylation of NH free-haloindoles.
Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36
Graphical Abstract
Scheme 1: Examples of BIMs used for their medicinal properties.
Scheme 2: Mechanisms for the synthesis of BIMs using protic or Lewis acids as catalysts.
Scheme 3: Synthesis of bis(indolyl)methanes using DBDMH.
Scheme 4: Competition experiments and synthesis of bis(indolyl)methanes using DBDMH.
Scheme 5: Proposed mechanism for formation of BIM of using DBDMH.
Scheme 6: Synthesis of bis(indolyl)methanes using I2.
Scheme 7: General reaction mechanism upon halogen bonding.
Scheme 8: Synthesis of bis(indolyl)methanes using I2, introduced by Ji.
Scheme 9: Synthesis of bis(indolyl)methanes using Br2 in CH3CN.
Scheme 10: Βidentate halogen-bond donors.
Scheme 11: Synthesis of bis(indolyl)methanes using bidentate halogen-bond donor 26.
Scheme 12: Proposed reaction mechanism.
Scheme 13: Synthesis of bis(indolyl)methanes using iodoalkyne as catalyst.
Scheme 14: Proposed reaction mechanism.
Scheme 15: Optimized reaction conditions used by Ramshini.
Scheme 16: Activation of the carbonyl group by HPA/TPI-Fe3O4.
Scheme 17: Synthesis of BIMs in the presence of nanoAg-Pt/SiO2-doped silicate.
Scheme 18: Mechanism of action proposed by Khalafi-Nezhad et al.
Scheme 19: Activation of the carbonyl group by the Cu–isatin Schiff base complex.
Scheme 20: Optimum reaction conditions published by Jain.
Scheme 21: Organocatalytic protocol utilizing nanoparticles introduced by Bankar.
Scheme 22: Activation of the carbonyl group by the AlCl3·6H2O-SDS-SiO2 complex.
Scheme 23: Optimal reaction conditions for the aforementioned nano-Fe3O4 based catalysts.
Scheme 24: Nanocatalytic protocol proposed by Kaur et al.
Scheme 25: Microwave approach introduced by Yuan.
Scheme 26: Microwave approach introduced by Zahran et al.
Scheme 27: Microwave irradiation protocol introduced by Bindu.
Scheme 28: Silica-supported microwave irradiation protocol.
Scheme 29: Proposed mechanism for formation of BIM by Nongkhlaw.
Scheme 30: Microwave-assisted synthesis of BIMs catalyzed by succinic acid.
Scheme 31: Proposed mechanism of action of MMO-4.
Scheme 32: Catalytic approach introduced by Muhammadpoor-Baltork et al.
Scheme 33: Reaction conditions used by Xiao-Ming.
Scheme 34: Ultrasonic irradiation-based protocol published by Saeednia.
Scheme 35: Pyruvic acid-mediated synthesis of BIMs proposed by Thopate.
Scheme 36: Synthesis of BIMs using [bmim]BF4 or [bmim]PF6 ionic liquids.
Scheme 37: Synthesis of BIMs utilizing In(OTf)3 in octylmethylimidazolium hexafluorophosphate as ionic liquid.
Scheme 38: FeCl3·6H2O-catalyzed synthesis of BIMs with use of ionic liquid.
Scheme 39: Synthesis of BIMs utilizing the [hmim]HSO4/EtOH catalytic system.
Scheme 40: Synthesis of BIMs utilizing acidic ionic liquid immobilized on silica gel (ILIS-SO2Cl).
Scheme 41: The [bmim][MeSO4]-catalyzed reaction of indole with various aldehydes.
Scheme 42: The role of [bmim][MeSO4] in catalyzing the reaction of indole with aldehydes.
Scheme 43: Synthesis of BIMs utilizing FeCl3-based ionic liquid ([BTBAC]Cl-FeCl3) as catalyst.
Scheme 44: Synthesis of BIMs using [Msim]Cl at room temperature.
Scheme 45: [Et3NH][H2PO4]-catalyzed synthesis of bis(indolyl)methanes.
Scheme 46: PILs-catalyzed synthesis of bis(indolyl)methanes.
Scheme 47: FSILs-mediated synthesis of bis(indolyl)methanes.
Scheme 48: Possible “release and catch” catalytic process.
Scheme 49: Synthesis of bis(indolyl)methanes by [DABCO-H][HSO4].
Scheme 50: Synthesis of bis(indolyl)methanes by [(THA)(SO4)].
Scheme 51: Synthesis of BBSI-Cl and BBSI-HSO4.
Scheme 52: Synthesis of BIMs in the presence of BBSI-Cl and BBSI-HSO4.
Scheme 53: Chemoselectivity of the present method.
Scheme 54: Synthesis of BIMs catalyzed by chitosan-supported ionic liquid.
Scheme 55: Proposed mechanism of action of CSIL.
Scheme 56: Optimization of the reaction in DESs.
Scheme 57: Synthesis of BIMs using ChCl/SnCl2 as DES.
Scheme 58: Synthesis of BIMs derivatives in presence of DES.
Scheme 59: BIMs synthesis in choline chloride/urea (CC/U).
Scheme 60: Flow chemistry-based synthesis of BIMs by Ley.
Scheme 61: Flow chemistry-based synthesis of BIMs proposed by Nam et al.
Scheme 62: Amino-catalyzed reaction of indole with propionaldehyde.
Scheme 63: Aminocatalytic synthesis of BIMs.
Scheme 64: Proposed mechanism for the aminocatalytic synthesis of BIMs.
Scheme 65: Enzymatic reaction of indole with aldehydes.
Scheme 66: Proposed mechanism for the synthesis of BIMs catalyzed by TLIM.
Scheme 67: Proposed reaction mechanism by Badsara.
Scheme 68: Mechanism proposed by D’Auria.
Scheme 69: Photoinduced thiourea catalysis.
Scheme 70: Proposed mechanism of photoacid activation.
Scheme 71: Proposed mechanism of action for CF3SO2Na.
Scheme 72: Proposed mechanism for the synthesis of BIMs by Mandawad.
Scheme 73: Proposed mechanism for the (a) acid generation and (b) synthesis of BIMs.
Scheme 74: a) Reaction conditions employed by Khaksar and b) activation of the carbonyl group by HFIP.
Scheme 75: Activation of the carbonyl group by the PPy@CH2Br through the formation of a halogen bond.
Scheme 76: Reaction conditions utilized by Mhaldar et al.
Scheme 77: a) Reaction conditions employed by López and b) activation of the carbonyl group by thiourea.
Scheme 78: Infrared irradiation approach introduced by Luna-Mora and his research group.
Scheme 79: Synthesis of BIMs with the use of the Fe–Zn BMOF.
Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12
Graphical Abstract
Figure 1: Representative dihydropyrido[1,2-a]indolone derivatives.
Scheme 1: Selected works for the construction of dihydropyrido[1,2-a]indolones and current methodology.
Scheme 2: Substrate scope of the cascade reaction.
Scheme 3: Radical trapping experiment.
Figure 2: UV–vis spectra of substrates; [1a] 0.33 M, [2a] 0.11 M.
Scheme 4: Plausible reaction mechanism.
Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110
Graphical Abstract
Figure 1: Examples of rhodanines and related five-membered heterocycles with interesting biological activitie...
Scheme 1: Synthesis of 5-benzylidenerhodanine derivatives. Conditions: areaction performed for 3 h at 60 °C. b...
Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106
Graphical Abstract
Scheme 1: Sulfur-containing bioactive molecules.
Scheme 2: Scandium-catalyzed synthesis of thiosulfonates.
Scheme 3: Palladium-catalyzed aryl(alkyl)thiolation of unactivated arenes.
Scheme 4: Catalytic cycle for Pd-catalyzed aryl(alkyl)thiolation of unactivated arenes.
Scheme 5: Iron- or boron-catalyzed C–H arylthiation of substituted phenols.
Scheme 6: Iron-catalyzed azidoalkylthiation of alkenes.
Scheme 7: Plausible mechanism for iron-catalyzed azidoalkylthiation of alkenes.
Scheme 8: BF3·Et2O‑mediated electrophilic cyclization of aryl alkynoates.
Scheme 9: Tentative mechanism for BF3·Et2O‑mediated electrophilic cyclization of aryl alkynoates.
Scheme 10: Construction of 6-substituted benzo[b]thiophenes.
Scheme 11: Plausible mechanism for construction of 6-substituted benzo[b]thiophenes.
Scheme 12: AlCl3‑catalyzed cyclization of N‑arylpropynamides with N‑sulfanylsuccinimides.
Scheme 13: Synthetic utility of AlCl3‑catalyzed cyclization of N‑arylpropynamides with N‑sulfanylsuccinimides.
Scheme 14: Sulfenoamination of alkenes with sulfonamides and N-sulfanylsuccinimides.
Scheme 15: Lewis acid/Brønsted acid controlled Pd-catalyzed functionalization of aryl C(sp2)–H bonds.
Scheme 16: Possible mechanism for Lewis acid/Brønsted acid controlled Pd-catalyzed functionalization of aryl C...
Scheme 17: FeCl3-catalyzed carbosulfenylation of unactivated alkenes.
Scheme 18: Copper-catalyzed electrophilic thiolation of organozinc halides.
Scheme 19: h-BN@Copper(II) nanomaterial catalyzed cross-coupling reaction of sulfoximines and N‑(arylthio)succ...
Scheme 20: AlCl3‑mediated cyclization and sulfenylation of 2‑alkyn-1-one O‑methyloximes.
Scheme 21: Lewis acid-promoted 2-substituted cyclopropane 1,1-dicarboxylates with sulfonamides and N-(arylthio...
Scheme 22: Lewis acid-mediated cyclization of β,γ-unsaturated oximes and hydrazones with N-(arylthio/seleno)su...
Scheme 23: Credible pathway for Lewis acid-mediated cyclization of β,γ-unsaturated oximes with N-(arylthio)suc...
Scheme 24: Synthesis of 4-chalcogenyl pyrazoles via chalcogenation/cyclization of α,β-alkynic hydrazones.
Scheme 25: Controllable synthesis of 3-thiolated pyrroles and pyrrolines.
Scheme 26: Possible mechanism for controllable synthesis of 3-thiolated pyrroles and pyrrolines.
Scheme 27: Co-catalyzed C2-sulfenylation and C2,C3-disulfenylation of indole derivatives.
Scheme 28: Plausible catalytic cycle for Co-catalyzed C2-sulfenylation and C2,C3-disulfenylation of indoles.
Scheme 29: C–H thioarylation of electron-rich arenes by iron(III) triflimide catalysis.
Scheme 30: Difunctionalization of alkynyl bromides with thiosulfonates and N-arylthio succinimides.·
Scheme 31: Suggested mechanism for difunctionalization of alkynyl bromides with thiosulfonates and N-arylthio ...
Scheme 32: Synthesis of thioesters, acyl disulfides, ketones, and amides by N-thiohydroxy succinimide esters.
Scheme 33: Proposed mechanism for metal-catalyzed selective acylation and acylthiolation.
Scheme 34: AlCl3-catalyzed synthesis of 3,4-bisthiolated pyrroles.
Scheme 35: α-Sulfenylation of aldehydes and ketones.
Scheme 36: Acid-catalyzed sulfetherification of unsaturated alcohols.
Scheme 37: Enantioselective sulfenylation of β-keto phosphonates.
Scheme 38: Organocatalyzed sulfenylation of 3‑substituted oxindoles.
Scheme 39: Sulfenylation and chlorination of β-ketoesters.
Scheme 40: Intramolecular sulfenoamination of olefins.
Scheme 41: Plausible mechanism for intramolecular sulfenoamination of olefins.
Scheme 42: α-Sulfenylation of 5H-oxazol-4-ones.
Scheme 43: Metal-free C–H sulfenylation of electron-rich arenes.
Scheme 44: TFA-promoted C–H sulfenylation indoles.
Scheme 45: Proposed mechanism for TFA-promoted C–H sulfenylation indoles.
Scheme 46: Organocatalyzed sulfenylation and selenenylation of 3-pyrrolyloxindoles.
Scheme 47: Organocatalyzed sulfenylation of S-based nucleophiles.
Scheme 48: Conjugate Lewis base Brønsted acid-catalyzed sulfenylation of N-heterocycles.
Scheme 49: Mechanism for activation of N-sulfanylsuccinimide by conjugate Lewis base Brønsted acid catalyst.
Scheme 50: Sulfenylation of deconjugated butyrolactams.
Scheme 51: Intramolecular sulfenofunctionalization of alkenes with phenols.
Scheme 52: Organocatalytic 1,3-difunctionalizations of Morita–Baylis–Hillman carbonates.
Scheme 53: Organocatalytic sulfenylation of β‑naphthols.
Scheme 54: Acid-promoted oxychalcogenation of o‑vinylanilides with N‑(arylthio/arylseleno)succinimides.
Scheme 55: Lewis base/Brønsted acid dual-catalytic C–H sulfenylation of aryls.
Scheme 56: Lewis base-catalyzed sulfenoamidation of alkenes.
Scheme 57: Cyclization of allylic amide using a Brønsted acid and tetrabutylammonium chloride.
Scheme 58: Catalytic electrophilic thiocarbocyclization of allenes with N-thiosuccinimides.
Scheme 59: Suggested mechanism for electrophilic thiocarbocyclization of allenes with N-thiosuccinimides.
Scheme 60: Chiral chalcogenide-catalyzed enantioselective hydrothiolation of alkenes.
Scheme 61: Proposed mechanism for chalcogenide-catalyzed enantioselective hydrothiolation of alkenes.
Scheme 62: Organocatalytic sulfenylation for synthesis a diheteroatom-bearing tetrasubstituted carbon centre.
Scheme 63: Thiolative cyclization of yne-ynamides.
Scheme 64: Synthesis of alkynyl and acyl disulfides from reaction of thiols with N-alkynylthio phthalimides.
Scheme 65: Oxysulfenylation of alkenes with 1-(arylthio)pyrrolidine-2,5-diones and alcohols.
Scheme 66: Arylthiolation of arylamines with (arylthio)-pyrrolidine-2,5-diones.
Scheme 67: Catalyst-free isothiocyanatoalkylthiation of styrenes.
Scheme 68: Sulfenylation of (E)-β-chlorovinyl ketones toward 3,4-dimercaptofurans.
Scheme 69: HCl-promoted intermolecular 1, 2-thiofunctionalization of aromatic alkenes.
Scheme 70: Possible mechanism for HCl-promoted 1,2-thiofunctionalization of aromatic alkenes.
Scheme 71: Coupling reaction of diazo compounds with N-sulfenylsuccinimides.
Scheme 72: Multicomponent reactions of disulfides with isocyanides and other nucleophiles.
Scheme 73: α-Sulfenylation and β-sulfenylation of α,β-unsaturated carbonyl compounds.
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, 1251–1258, doi:10.3762/bjoc.19.93
Graphical Abstract
Figure 1: Medicines containing an imidazole nucleus.
Scheme 1: Synthesis of N-substituted imidazole derivatives from MBH adducts.
Scheme 2: Proposed mechanism for the allylation of imidazole with alcohol 4a.
Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82
Graphical Abstract
Scheme 1: Oxidation of heteroatoms.
Scheme 2: Graphical representation comparing A electrochemistry and B photoredox catalysis using a semiconduc...
Figure 1: Study of additives. A) Effect of the addition of 1 equiv of various acids and bases to the standard...
Scheme 3: Substrate scope with reaction times and isolated yields. 1 mmol (1 equiv) substrate was reacted in ...
Scheme 4: Setup used in the flow experiment for the triphenylphosphine oxidation.
Scheme 5: Proposed extra alternative pathway.
Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76
Graphical Abstract
Figure 1: Representative examples of N-arylamines.
Scheme 1: N-Arylation of amines with hypervalent iodine reagents.
Scheme 2: N-Arylation of primary amines with iodonium ylide. Reaction conditions: 0.2 mmol aniline 1, 0.24 mm...
Scheme 3: N-Arylation of secondary amines with iodonium ylide.
Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71
Graphical Abstract
Figure 1: Various pyrrole containing molecules.
Scheme 1: Various synthestic protocols for the synthesis of pyrroles.
Figure 2: A tree-diagram showing various conventional and green protocols for Clauson-Kaas pyrrole synthesis.
Scheme 2: A general reaction of Clauson–Kaas pyrrole synthesis and proposed mechanism.
Scheme 3: AcOH-catalyzed synthesis of pyrroles 5 and 7.
Scheme 4: Synthesis of N-substituted pyrroles 9.
Scheme 5: P2O5-catalyzed synthesis of N-substituted pyrroles 11.
Scheme 6: p-Chloropyridine hydrochloride-catalyzed synthesis of pyrroles 13.
Scheme 7: TfOH-catalyzed synthesis of N-sulfonylpyrroles 15, N-sulfonylindole 16, N-sulfonylcarbazole 17.
Scheme 8: Scandium triflate-catalyzed synthesis of N-substituted pyrroles 19.
Scheme 9: MgI2 etherate-catalyzed synthesis and proposed mechanism of N-arylpyrrole derivatives 21.
Scheme 10: Nicotinamide catalyzed synthesis of pyrroles 23.
Scheme 11: ZrOCl2∙8H2O catalyzed synthesis and proposed mechanism of pyrrole derivatives 25.
Scheme 12: AcONa catalyzed synthesis of N-substituted pyrroles 27.
Scheme 13: Squaric acid-catalyzed synthesis and proposed mechanism of N-substituted pyrroles 29.
Figure 3: Reusability of catalyst γ-Fe2O3@SiO2-Sb-IL in six cycles.
Scheme 14: Magnetic nanoparticle-supported antimony catalyst used in the synthesis of N-substituted pyrroles 31...
Scheme 15: Iron(III) chloride-catalyzed synthesis of N-substituted pyrroles 33.
Scheme 16: Copper-catalyzed Clauson–Kaas synthesis and mechanism of pyrroles 35.
Scheme 17: β-CD-SO3H-catalyzed synthesis and proposed mechanism of pyrroles 37.
Figure 4: Recyclability of β-cyclodextrin-SO3H.
Scheme 18: Solvent-free and catalyst-free synthesis and plausible mechanism of N-substituted pyrroles 39.
Scheme 19: Nano-sulfated TiO2-catalyzed synthesis of N-substituted pyrroles 41.
Figure 5: Plausible mechanism for the formation of N-substituted pyrroles catalyzed by nano-sulfated TiO2 cat...
Scheme 20: Copper nitrate-catalyzed Clauson–Kaas synthesis and mechanism of N-substituted pyrroles 43.
Scheme 21: Synthesis of N-substituted pyrroles 45 by using Co catalyst Co/NGr-C@SiO2-L.
Scheme 22: Zinc-catalyzed synthesis of N-arylpyrroles 47.
Scheme 23: Silica sulfuric acid-catalyzed synthesis of pyrrole derivatives 49.
Scheme 24: Bismuth nitrate-catalyzed synthesis of pyrroles 51.
Scheme 25: L-(+)-tartaric acid-choline chloride-catalyzed Clauson–Kaas synthesis and plausible mechanism of py...
Scheme 26: Microwave-assisted synthesis of N-substituted pyrroles 55 in AcOH or water.
Scheme 27: Synthesis of pyrrole derivatives 57 using a nano-organocatalyst.
Figure 6: Nano-ferric supported glutathione organocatalyst.
Scheme 28: Microwave-assisted synthesis of N-substituted pyrroles 59 in water.
Scheme 29: Iodine-catalyzed synthesis and proposed mechanism of pyrroles 61.
Scheme 30: H3PW12O40/SiO2-catalyzed synthesis of N-substituted pyrroles 63.
Scheme 31: Fe3O4@-γ-Fe2O3-SO3H-catalyzed synthesis of pyrroles 65.
Scheme 32: Mn(NO3)2·4H2O-catalyzed synthesis and proposed mechanism of pyrroles 67.
Scheme 33: p-TsOH∙H2O-catalyzed (method 1) and MW-assisted (method 2) synthesis of N-sulfonylpyrroles 69.
Scheme 34: ([hmim][HSO4]-catalyzed Clauson–Kaas synthesis of pyrroles 71.
Scheme 35: Synthesis of N-substituted pyrroles 73 using K-10 montmorillonite catalyst.
Scheme 36: CeCl3∙7H2O-catalyzed Clauson–Kaas synthesis of pyrroles 75.
Scheme 37: Synthesis of N-substituted pyrroles 77 using Bi(NO3)3∙5H2O.
Scheme 38: Oxone-catalyzed synthesis and proposed mechanism of N-substituted pyrroles 79.
Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39
Graphical Abstract
Scheme 1: Previous works (A–D) and the extension (this work).
Scheme 2: Synthesis of diethyl 2-diazo-1,1,3,3,3-pentafluoropropylphosphonate (5).
Scheme 3: Scope of the cyclopropanation. Reaction conditions: alkene (0.15 mmol), diazo compound 5 (0.1 mmol)...
Figure 1: 19F,1H-HOESY spectrum of compound 6c.
Scheme 4: Scope of the cyclopropanation. Reaction conditions: alkene (0.15 mmol), diazo compound 5 (0.1 mmol)...
Scheme 5: Addition of CuI to the diazo compound 5.
Scheme 6: Possible addition of styrene to Int2 yielding Int4_1 and Int4_2 through Int3_1 and Int3_2.
Scheme 7: Possible addition of styrene to Int2 yielding Int4_3 and Int4_4 without further intermediates.
Scheme 8: Formation of the products Pr1 to Pr4.
Beilstein J. Org. Chem. 2023, 19, 231–244, doi:10.3762/bjoc.19.22
Graphical Abstract
Figure 1: Representative drug molecules based on pyrazole, thioamide, and amide derivatives.
Figure 2: Previous and present findings for the synthesis of thioamide derivatives.
Scheme 1: Synthesis of pyrazole C-3-tethered thioamides.
Scheme 2: Synthesis of pyrazole C-4-tethered thioamides.
Scheme 3: Metal- and catalyst-free preparation of pyrazole C-5-linked thioamide conjugates.
Scheme 4: Synthesis of 4-iodopyrazole C-3-tethered thioamides.
Scheme 5: Gram-scale scope of the current protocol.
Scheme 6: Control experiment.
Scheme 7: H2O2-mediated synthesis of pyrazole-pyridine conjugates with amide tethers.
Scheme 8: Synthesis of pyrazole-pyridine conjugates 9F and 10F having amide tethers.
Scheme 9: A tentative mechanism for the formation of pyrazole conjugates with thioamide and amide linkage.
Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179
Graphical Abstract
Scheme 1: Organocatalysis classification used in the present perspective.
Scheme 2: Oxidative processes catalyzed by amines.
Scheme 3: N-Heterocyclic carbene (NHC) catalysis in oxidative functionalization of aldehydes.
Scheme 4: Examples of asymmetric oxidative processes catalyzed by chiral Brønsted acids.
Scheme 5: Asymmetric aerobic α-hydroxylation of lactams under phase-transfer organocatalysis conditions emplo...
Scheme 6: Selective CH-oxidation of methylarenes to aldehydes or carboxylic acids.
Scheme 7: An example of the regioselective CH-amination by a sterically hindered imide-N-oxyl radical precurs...
Scheme 8: CH-amination of ethylbenzene and CH-fluorination of aldehydes catalyzed by N-hydroxybenzimidazoles,...
Scheme 9: Mixed hetero-/homogeneous TiO2/N-hydroxyimide photocatalysis in the selective benzylic oxidation.
Scheme 10: Electrochemical benzylic iodination and benzylation of pyridine by benzyl iodides generated in situ...
Scheme 11: Electrochemical oxidative C–O/C–N coupling of alkylarenes with NHPI. Electrolysis conditions: Const...
Scheme 12: Chemoselective alcohol oxidation catalyzed by TEMPO.
Scheme 13: ABNO-catalyzed oxidative C–N coupling of primary alcohols with primary amines.
Scheme 14: ACT-catalyzed electrochemical oxidation of primary alcohols and aldehydes to carboxylic acids.
Scheme 15: Electrocatalytic oxidation of benzylic alcohols by a TEMPO derivative immobilized on a graphite ano...
Scheme 16: Electrochemical oxidation of carbamates of cyclic amines to lactams and oxidative cyanation of amin...
Scheme 17: Hydrogen atom transfer (HAT) and single-electron transfer (SET) as basic principles of amine cation...
Scheme 18: Electrochemical quinuclidine-catalyzed oxidation involving unactivated C–H bonds.
Scheme 19: DABCO-mediated photocatalytic C–C cross-coupling involving aldehyde C–H bond cleavage.
Scheme 20: DABCO-derived cationic catalysts in inactivated C–H bond cleavage for alkyl radical addition to ele...
Scheme 21: Electrochemical diamination and dioxygenation of vinylarenes catalyzed by triarylamines.
Scheme 22: Electrochemical benzylic oxidation mediated by triarylimidazoles.
Scheme 23: Thiyl radical-catalyzed CH-arylation of allylic substrates by aryl cyanides.
Scheme 24: Synthesis of redox-active alkyl tetrafluoropyridinyl sulfides by unactivated C–H bond cleavage by t...
Scheme 25: Main intermediates in quinone oxidative organocatalysis.
Scheme 26: Electrochemical DDQ-catalyzed intramolecular dehydrogenative aryl–aryl coupling.
Scheme 27: DDQ-mediated cross-dehydrogenative C–N coupling of benzylic substrates with azoles.
Scheme 28: Biomimetic o-quinone-catalyzed benzylic alcohol oxidation.
Scheme 29: Electrochemical synthesis of secondary amines by oxidative coupling of primary amines and benzylic ...
Scheme 30: General scheme of dioxirane and oxaziridine oxidative organocatalysis.
Scheme 31: Dioxirane organocatalyzed CH-hydroxylation involving aliphatic C(sp3)–H bonds.
Scheme 32: Enantioselective hydroxylation of CH-acids catalyzed by chiral oxaziridines.
Scheme 33: Iodoarene-organocatalyzed vinylarene diamination.
Scheme 34: Iodoarene-organocatalyzed asymmetric CH-hydroxylation of benzylic substrates.
Scheme 35: Iodoarene-organocatalyzed asymmetric difluorination of alkenes with migration of aryl or methyl gro...
Scheme 36: Examples of 1,2-diiodo-4,5-dimethoxybenzene-catalyzed electrochemical oxidative heterocyclizations.
Scheme 37: Electrochemical N-ammonium ylide-catalyzed CH-oxidation.
Scheme 38: Oxidative dimerization of aryl- and alkenylmagnesium compounds catalyzed by quinonediimines.
Scheme 39: FLP-catalyzed dehydrogenation of N-substituted indolines.
Beilstein J. Org. Chem. 2022, 18, 1532–1538, doi:10.3762/bjoc.18.162
Graphical Abstract
Figure 1: Selected examples of biologically active natural products bearing a spirofuranoxindole moiety.
Scheme 1: Synthesis of spiro[dihydrofuran-2,3'-oxindoles] from enones and diazooxindoles.
Scheme 2: Cycloaddition reactions of [e]-fused 1H-pyrrole-2,3-diones.
Scheme 3: The model reaction of FPD 1a and diazooxindole 2a.
Scheme 4: The reaction of FPD 1k with diazooxindole 2a.
Scheme 5: A) Plausible mechanism of formal [4 + 1] cycloaddition of FPDs 1 with diazooxindoles 2 (negative ch...
Beilstein J. Org. Chem. 2022, 18, 999–1008, doi:10.3762/bjoc.18.100
Graphical Abstract
Figure 1: Representative examples of important halogen-containing aryl derivatives.
Scheme 1: Strategies for halogenation of aromatic compounds using NXS.
Scheme 2: General scheme of PEG-400-assisted halogenation of phenols and anilines in an automated grinder usi...
Scheme 3: Monohalogenation of phenols and anilines by automated grinding with NXS. All yields refer to the is...
Scheme 4: Dihalogenation of phenols and anilines with NXS by automated grinding. All yields refer to the isol...
Scheme 5: Gram-scale monobromination of p-cresol by NBS in the automated grinder.
Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43
Graphical Abstract
Figure 1: Natural bioactive naphthoquinones.
Figure 2: Chemical structures of vitamins K.
Figure 3: Redox cycle of menadione.
Scheme 1: Selected approaches for menadione synthesis using silver(I) as a catalyst.
Scheme 2: Methylation approaches for the preparation of menadione from 1,4-naphthoquinone using tert-butyl hy...
Scheme 3: Methylation approach of 1,4-naphthoquinone using i) rhodium complexes/methylboronic acid and ii) bi...
Scheme 4: Synthesis of menadione (10) from itaconic acid.
Scheme 5: Menadione synthesis via Diels–Alder reaction.
Scheme 6: Synthesis of menadione (10) using p-cresol as a synthetic precursor.
Scheme 7: Synthesis of menadione (10) via demethoxycarbonylating annulation of methyl methacrylate.
Scheme 8: Furan 34 used as a diene in a Diels–Alder reaction for the synthesis of menadione (10).
Scheme 9: o-Toluidine as a dienophile in a Diels–Alder reaction for the synthesis of menadione (10).
Scheme 10: Representation of electrochemical synthesis of menadione.
Figure 4: Reaction sites and reaction types of menadione as substrate.
Scheme 11: DBU-catalyzed epoxidation of menadione (10).
Scheme 12: Phase-transfer catalysis for the epoxidation of menadione.
Scheme 13: Menadione epoxidation using a hydroperoxide derived from (+)-norcamphor.
Scheme 14: Enantioselective Diels–Alder reaction for the synthesis of asymmetric quinone 50 catalyzed by a chi...
Scheme 15: Optimized reaction conditions for the synthesis of anthra[9,1-bc]pyranone.
Scheme 16: Synthesis of anthra[9,1-bc]furanone, anthra[9,1-bc]pyridine, and anthra[9,1-bc]pyrrole derivatives.
Scheme 17: Synthesis of derivatives employing protected trienes.
Scheme 18: Synthesis of cyclobutene derivatives of menadione.
Scheme 19: Menadione reduction reactions using sodium hydrosulfite.
Scheme 20: Green methodology for menadiol synthesis and pegylation.
Scheme 21: Menadione reduction by 5,6-O-isopropylidene-ʟ-ascorbic acid under UV light irradiation.
Scheme 22: Selected approaches of menadione hydroacetylation to diacetylated menadiol.
Scheme 23: Thiele–Winter reaction catalyzed by Bi(OTf)3.
Scheme 24: Carbonyl condensation of menadione using resorcinol and a hydrazone derivative.
Scheme 25: Condensation reaction of menadione with thiosemicarbazide.
Scheme 26: Condensation reaction of menadione with acylhydrazides.
Scheme 27: Menadione derivatives functionalized with organochalcogens.
Scheme 28: Synthesis of selenium-menadione conjugates derived from chloromethylated menadione 84.
Scheme 29: Menadione alkylation by the Kochi–Anderson method.
Scheme 30: Menadione alkylation by diacids.
Scheme 31: Menadione alkylation by heterocycles-substituted carboxylic acids.
Scheme 32: Menadione alkylation by bromoalkyl-substituted carboxylic acids.
Scheme 33: Menadione alkylation by complex carboxylic acids.
Scheme 34: Kochi–Anderson method variations for the menadione alkylation via oxidative decarboxylation of carb...
Scheme 35: Copper-catalyzed menadione alkylation via free radicals.
Scheme 36: Nickel-catalyzed menadione cyanoalkylation.
Scheme 37: Iron-catalyzed alkylation of menadione.
Scheme 38: Selected approaches to menadione alkylation.
Scheme 39: Menadione acylation by photo-Friedel–Crafts acylation reported by Waske and co-workers.
Scheme 40: Menadione acylation by Westwood procedure.
Scheme 41: Synthesis of 3-benzoylmenadione via metal-free TBAI/TBHP system.
Scheme 42: Michael-type addition of amines to menadione reported by Kallmayer.
Scheme 43: Synthesis of amino-menadione derivatives using polyalkylamines.
Scheme 44: Selected examples for the synthesis of different amino-substituted menadione derivatives.
Scheme 45: Selected examples of Michael-type addition of complex amines to menadione (10).
Scheme 46: Addition of different natural α-amino acids to menadione.
Scheme 47: Michael-type addition of amines to menadione using silica-supported perchloric acid.
Scheme 48: Indolylnaphthoquinone or indolylnaphthalene-1,4-diol synthesis reported by Yadav et al.
Scheme 49: Indolylnaphthoquinone synthesis reported by Tanoue and co-workers.
Scheme 50: Indolylnaphthoquinone synthesis from menadione by Escobeto-González and co-workers.
Scheme 51: Synthesis of menadione analogues functionalized with thiols.
Scheme 52: Synthesis of menadione-derived symmetrical derivatives through reaction with dithiols.
Scheme 53: Mercaptoalkyl acids as nucleophiles in Michael-type addition reaction to menadione.
Scheme 54: Reactions of menadione (10) with cysteine derivatives for the synthesis of quinoproteins.
Scheme 55: Synthesis of menadione-glutathione conjugate 152 by Michael-type addition.
Beilstein J. Org. Chem. 2022, 18, 70–76, doi:10.3762/bjoc.18.6
Graphical Abstract
Figure 1: Oxazoline-containing bioactive natural products.
Scheme 1: Synthetic methods of oxazoline derivatives.
Scheme 2: Scopes of aziridines and diazo esters.
Scheme 3: Proposed reaction mechanism.
Scheme 4: Direction of tautomerization.