Search for "phthalimide" in Full Text gives 105 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114
Graphical Abstract
Figure 1: Some significant triazole derivatives [8,23-27].
Scheme 1: A general comparison between synthetic routes for disubstituted 1,2,3-triazole derivatives and full...
Scheme 2: Synthesis of formyltriazoles 3 from the treatment of α-bromoacroleins 1 with azides 2.
Scheme 3: A probable mechanism for the synthesis of formyltriazoles 5 from the treatment of α-bromoacroleins 1...
Scheme 4: Synthesis of 1,4,5-trisubstituted 1,2,3-triazoles 8 from the reaction of aryl azides 7 with enamino...
Scheme 5: Proposed mechanism for the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles from the reaction of a...
Scheme 6: Synthesis of 1,4,5-trisubstituted 1,2,3-triazoles 11 from the reaction of primary amines 10 with 1,...
Scheme 7: The proposed mechanism for the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles 11 from the reacti...
Scheme 8: Synthesis of fully decorated 1,2,3-triazoles 19 containing a sulfur-based side chain.
Scheme 9: Mechanism for the formation of fully decorated 1,2,3-triazoles 19 containing a sulfur-based side ch...
Scheme 10: Synthesis of fully decorated 1,2,3-triazole compounds 25 through the regioselective addition and cy...
Scheme 11: A reasonable mechanism for the synthesis of fully decorated 1,2,3-triazole compounds 25 through the...
Scheme 12: Synthesis of 1,4,5-trisubstituted glycosyl-containing 1,2,3-triazole derivatives 30 from the reacti...
Scheme 13: Synthesis of 1,4,5-trisubstituted 1,2,3-triazoles 34 via intramolecular cyclization reaction of ket...
Scheme 14: Synthesis of fully decorated 1,2,3-triazoles 38 from the reaction of aldehydes 35, amines 36, and α...
Scheme 15: A reasonable mechanism for the synthesis of fully decorated 1,2,3-triazoles 38 from the reaction of...
Scheme 16: Synthesis of functionally rich double C- and N-vinylated 1,2,3-triazoles 45 and 47.
Scheme 17: Synthesis of disubstituted 4-chloro-, 4-bromo-, and 4-iodo-1,2,3-triazoles 50.
Scheme 18: a) A general route for SPAAC in polymer chemistry and b) synthesis of a novel pH-sensitive polymeri...
Scheme 19: Synthesis of 5-allenyl-1,2,3-triazoles 60 by the treatment of alkynes 57, azides 58, and propargyli...
Scheme 20: A reasonable mechanism for the synthesis of 5-allenyl-1,2,3-triazoles 60 by the treatment of alkyne...
Scheme 21: Synthesis of 5‐alkynyl-1,2,3-triazoles 69.
Scheme 22: A reasonable mechanism for the synthesis of 5‐alkynyl-1,2,3-triazoles 69.
Scheme 23: Synthesis of sulfur-cycle-fused 1,2,3-triazoles 75 and 77.
Scheme 24: A reasonable mechanism for the synthesis of sulfur-cycle-fused 1,2,3‐triazoles 75 and 77.
Scheme 25: Synthesis of 5-selanyltriazoles 85 from the reaction of ethynylstibanes 82, organic azides 83, and ...
Scheme 26: A mechanism for the synthesis of 5-selanyltriazoles 85 from the reaction of ethynylstibanes 82, org...
Scheme 27: Synthesis of trisubstituted triazoles containing an Sb substituent at position C5 in 93 and 5-unsub...
Scheme 28: Synthesis of asymmetric triazole disulfides 98 from disulfide-containing tert-butyltosyl disulfide 97...
Scheme 29: A mechanism for the synthesis of asymmetric triazole disulfides 98 from disulfide-containing tert-bu...
Scheme 30: Synthesis of triazole-fused sultams 104.
Scheme 31: Synthesis of 1,2,3-triazole-fused tricyclic heterocycles 106.
Scheme 32: A reasonable mechanism for the synthesis of 1,2,3-triazole-fused tricyclic heterocycles 106.
Scheme 33: Synthesis of 5-aryl-substituted 1,2,3-triazole derivatives 112.
Scheme 34: A reasonable mechanism for the synthesis of 5-aryl-substituted 1,2,3-triazole derivatives 112.
Scheme 35: Synthesis of 1,4,5-trisubstituted 1,2,3-triazole-5-carboxamides 119.
Scheme 36: A probable mechanism for the synthesis of 1,4,5-trisubstituted 1,2,3-triazole-5-carboxamides 119.
Scheme 37: Synthesis of fully decorated triazoles 125 via the Pd/C-catalyzed arylation of disubstituted triazo...
Scheme 38: Synthesis of triazolo[1,5-a]indolones 131.
Scheme 39: Synthesis of unsymmetrically substituted triazole-fused enediyne systems 135 and 5-aryl-4-ethynyltr...
Scheme 40: Synthesis of Pd/Cu-BNP 139 and application of 139 in the synthesis of polycyclic triazoles 142.
Scheme 41: A probable mechanism for the synthesis of polycyclic triazoles 142.
Scheme 42: Synthesis of highly functionalized 1,2,3-triazole-fused 5-, 6-, and 7-membered rings 152–154.
Scheme 43: A probable mechanism for the synthesis of highly functionalized 1,2,3-triazole-fused 5-, 6-, and 7-...
Scheme 44: Synthesis of fully functionalized 1,2,3-triazolo-fused chromenes 162, 164, and 166 via the intramol...
Scheme 45: Ru-catalyzed synthesis of fully decorated triazoles 172.
Scheme 46: Synthesis of 4-cyano-1,2,3-triazoles 175.
Scheme 47: Synthesis of functionalized triazoles from the reaction of 1-alkyltriazenes 176 and azides 177 and ...
Scheme 48: Mechanism for the synthesis of functionalized triazoles from the reaction of 1-alkyltriazenes 176 a...
Beilstein J. Org. Chem. 2021, 17, 771–799, doi:10.3762/bjoc.17.67
Graphical Abstract
Scheme 1: The electron transfer process in EDA complexes.
Scheme 2: Synthesis of benzo[b]phosphorus oxide 3 initiated by an EDA complex.
Scheme 3: Mechanism of the synthesis of quinoxaline derivative 7.
Scheme 4: Synthesis of imidazole derivative 10 initiated by an EDA complex.
Scheme 5: Synthesis of sulfamoylation product 12 initiated by an EDA complex.
Scheme 6: Mechanism of the synthesis of sulfamoylation product 12.
Scheme 7: Synthesis of indole derivative 22 initiated by an EDA complex.
Scheme 8: Synthesis of perfluoroalkylated pyrimidines 26 initiated by an EDA complex.
Scheme 9: Synthesis of phenanthridine derivative 29 initiated by an EDA complex.
Scheme 10: Synthesis of cis-tetrahydroquinoline derivative 32 initiated by an EDA complex.
Scheme 11: Mechanism of the synthesis of cis-tetrahydroquinoline derivative 32.
Scheme 12: Synthesis of phenanthridine derivative 38 initiated by an EDA complex.
Scheme 13: Synthesis of spiropyrroline derivative 40 initiated by an EDA complex.
Scheme 14: Synthesis of benzothiazole derivative 43 initiated by an EDA complex.
Scheme 15: Synthesis of perfluoroalkyl-s-triazine derivative 45 initiated by an EDA complex.
Scheme 16: Synthesis of indoline derivative 47 initiated by an EDA complex.
Scheme 17: Mechanism of the synthesis of spirocyclic indoline derivative 47.
Scheme 18: Synthesis of cyclobutane product 50 initiated by an EDA complex.
Scheme 19: Mechanism of the synthesis of spirocyclic indoline derivative 50.
Scheme 20: Synthesis of 1,3-oxazolidine compound 59 initiated by an EDA complex.
Scheme 21: Synthesis of trifluoromethylated product 61 initiated by an EDA complex.
Scheme 22: Synthesis of indole alkylation product 64 initiated by an EDA complex.
Scheme 23: Synthesis of perfluoroalkylation product 67 initiated by an EDA complex.
Scheme 24: Synthesis of hydrotrifluoromethylated product 70 initiated by an EDA complex.
Scheme 25: Synthesis of β-trifluoromethylated alkyne product 71 initiated by an EDA complex.
Scheme 26: Mechanism of the synthesis of 2-phenylthiophene derivative 74.
Scheme 27: Synthesis of allylated product 80 initiated by an EDA complex.
Scheme 28: Synthesis of trifluoromethyl-substituted alkynyl product 84 initiated by an EDA complex.
Scheme 29: Synthesis of dearomatized fluoroalkylation product 86 initiated by an EDA complex.
Scheme 30: Mechanism of the synthesis of dearomatized fluoroalkylation product 86.
Scheme 31: Synthesis of C(sp3)–H allylation product 91 initiated by an EDA complex.
Scheme 32: Synthesis of perfluoroalkylation product 93 initiated by an EDA complex.
Scheme 33: Synthesis of spirocyclic indolene derivative 95 initiated by an EDA complex.
Scheme 34: Synthesis of perfluoroalkylation product 97 initiated by an EDA complex.
Scheme 35: Synthesis of alkylated indole derivative 100 initiated by an EDA complex.
Scheme 36: Mechanism of the synthesis of alkylated indole derivative 100.
Scheme 37: Synthesis of arylated oxidized indole derivative 108 initiated by an EDA complex.
Scheme 38: Synthesis of 4-ketoaldehyde derivative 111 initiated by an EDA complex.
Scheme 39: Mechanism of the synthesis of 4-ketoaldehyde derivative 111.
Scheme 40: Synthesis of perfluoroalkylated olefin 118 initiated by an EDA complex.
Scheme 41: Synthesis of alkylation product 121 initiated by an EDA complex.
Scheme 42: Synthesis of acylation product 123 initiated by an EDA complex.
Scheme 43: Mechanism of the synthesis of acylation product 123.
Scheme 44: Synthesis of trifluoromethylation product 126 initiated by an EDA complex.
Scheme 45: Synthesis of unnatural α-amino acid 129 initiated by an EDA complex.
Scheme 46: Synthesis of thioether derivative 132 initiated by an EDA complex.
Scheme 47: Synthesis of S-aryl dithiocarbamate product 135 initiated by an EDA complex.
Scheme 48: Mechanism of the synthesis of S-aryl dithiocarbamate product 135.
Scheme 49: Synthesis of thioether product 141 initiated by an EDA complex.
Scheme 50: Mechanism of the synthesis of borate product 144.
Scheme 51: Synthesis of boronation product 148 initiated by an EDA complex.
Scheme 52: Synthesis of boration product 151 initiated by an EDA complex.
Scheme 53: Synthesis of boronic acid ester derivative 154 initiated by an EDA complex.
Scheme 54: Synthesis of β-azide product 157 initiated by an EDA complex.
Scheme 55: Decarboxylation reaction initiated by an EDA complex.
Scheme 56: Synthesis of amidated product 162 initiated by an EDA complex.
Scheme 57: Synthesis of diethyl phenylphosphonate 165 initiated by an EDA complex.
Scheme 58: Mechanism of the synthesis of diethyl phenylphosphonate derivative 165.
Scheme 59: Synthesis of (Z)-2-iodovinyl phenyl ether 168 initiated by an EDA complex.
Scheme 60: Mechanism of the synthesis of (Z)-2-iodovinyl phenyl ether derivative 168.
Scheme 61: Dehalogenation reaction initiated by an EDA complex.
Beilstein J. Org. Chem. 2021, 17, 551–557, doi:10.3762/bjoc.17.49
Graphical Abstract
Scheme 1: Origin of the reaction design.
Scheme 2: Substrate scope of disulfides.
Scheme 3: Substrate scope of unactivated alkenes.
Scheme 4: Control experiments.
Scheme 5: Proposed mechanism.
Beilstein J. Org. Chem. 2020, 16, 2903–2910, doi:10.3762/bjoc.16.239
Graphical Abstract
Figure 1: Biologically active imidazo[1,5-a]pyridines.
Scheme 1: Activation of nitroalkanes towards nucleophilic attack by amines.
Scheme 2: Mechanistic rationale.
Scheme 3: Reaction of the N-tosylate 17 with electrophilic nitroalkanes.
Scheme 4: Reaction of 2-(aminomethyl)pyridine (12) with electrophilic nitroalkanes.
Scheme 5: Reaction of the 2-(aminomethyl)quinolines 18 with electrophilic nitroalkanes.
Scheme 6: Reactivity of α-nitroacetophenone (1h) and α-nitroacetic ester (1i).
Beilstein J. Org. Chem. 2020, 16, 2687–2700, doi:10.3762/bjoc.16.219
Graphical Abstract
Figure 1: Schematic illustration of the analyte-induced crosslinking of gold nanoparticles containing a mixtu...
Scheme 1: Syntheses of the ligands rac-1 and (R)-1. Conditions: i) TsCl, NaOH, THF, 0 °C, 60 min → 25 °C, 80 ...
Scheme 2: Synthesis of ligand 2. Conditions: i) potassium phthalimide, DMF, 25 °C, 18 h, 67%; ii) 2,2'-dipico...
Figure 2: Photographs of solutions of NPrac-1 in water (0.25 mg/mL) containing different sodium salts at a co...
Figure 3: Sections of the 1H NMR spectra of solutions of NP25 in D2O/CD3OD 1:2 (v/v) between 8.9 and 3.9 ppm ...
Figure 4: Images of vials containing solutions of NP10-Zn (0.25 mg/mL) in water/methanol 1:2 (v/v) and additi...
Figure 5: Photograph of the solutions of the competition experiment. Vial (a) only contained NP10-Zn (and the...
Figure 6: UV–vis spectra of NP10-Zn (0.25 mg/mL in the initial measurement) in water/methanol 1:2 (v/v) conta...
Figure 7: TEM images of NP10-Zn (0.25 mg/mL) in water/methanol 1:2 (v/v) before (a) and after the addition of...
Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197
Graphical Abstract
Scheme 1: Amine/photoredox-catalysed α-alkylation of aldehydes with alkyl bromides bearing electron-withdrawi...
Scheme 2: Amine/HAT/photoredox-catalysed α-functionalisation of aldehydes using alkenes.
Scheme 3: Amine/cobalt/photoredox-catalysed α-functionalisation of ketones and THIQs.
Scheme 4: Amine/photoredox-catalysed α-functionalisation of aldehydes or ketones with imines. (a) Using keton...
Scheme 5: Bifunctional amine/photoredox-catalysed enantioselective α-functionalisation of aldehydes.
Scheme 6: Bifunctional amine/photoredox-catalysed α-functionalisation of aldehydes using amine catalysts via ...
Scheme 7: Amine/photoredox-catalysed RCA of iminium ion intermediates. (a) Synthesis of quaternary stereocent...
Scheme 8: Bifunctional amine/photoredox-catalysed RCA of enones in a radical chain reaction initiated by an i...
Scheme 9: Bifunctional amine/photoredox-catalysed RCA reactions of iminium ions with different radical precur...
Scheme 10: Bifunctional amine/photoredox-catalysed radical cascade reactions between enones and alkenes with a...
Scheme 11: Amine/photocatalysed photocycloadditions of iminium ion intermediates. (a) External photocatalyst u...
Scheme 12: Amine/photoredox-catalysed addition of acrolein (94) to iminium ions.
Scheme 13: Dual NHC/photoredox-catalysed acylation of THIQs.
Scheme 14: NHC/photocatalysed spirocyclisation via photoisomerisation of an extended Breslow intermediate.
Scheme 15: CPA/photoredox-catalysed aza-pinacol cyclisation.
Scheme 16: CPA/photoredox-catalysed Minisci-type reaction between azaarenes and α-amino radicals.
Scheme 17: CPA/photoredox-catalysed radical additions to azaarenes. (a) α-Amino radical or ketyl radical addit...
Scheme 18: CPA/photoredox-catalysed reduction of azaarene-derived substrates. (a) Reduction of ketones. (b) Ex...
Scheme 19: CPA/photoredox-catalysed radical coupling reactions of α-amino radicals with α-carbonyl radicals. (...
Scheme 20: CPA/photoredox-catalysed Povarov reaction.
Scheme 21: CPA/photoredox-catalysed reactions with imines. (a) Decarboxylative imine generation followed by Po...
Scheme 22: Bifunctional CPA/photocatalysed [2 + 2] photocycloadditions.
Scheme 23: PTC/photocatalysed oxygenation of 1-indanone-derived β-keto esters.
Scheme 24: PTC/photoredox-catalysed perfluoroalkylation of 1-indanone-derived β-keto esters via a radical chai...
Scheme 25: Bifunctional hydrogen bonding/photocatalysed intramolecular [2 + 2] photocycloadditions of quinolon...
Scheme 26: Bifunctional hydrogen bonding/photocatalysed intramolecular RCA cyclisation of a quinolone.
Scheme 27: Bifunctional hydrogen bonding/photocatalysed intramolecular [2 + 2] photocycloadditions of quinolon...
Scheme 28: Bifunctional hydrogen bonding/photocatalysed [2 + 2] photocycloaddition reactions. (a) First use of...
Scheme 29: Bifunctional hydrogen bonding/photocatalysed deracemisation of allenes.
Scheme 30: Bifunctional hydrogen bonding/photocatalysed deracemisation reactions. (a) Deracemisation of sulfox...
Scheme 31: Bifunctional hydrogen bonding/photocatalysed intramolecular [2 + 2] photocycloaddition of coumarins....
Scheme 32: Bifunctional hydrogen bonding/photocatalysed [2 + 2] photocycloadditions of quinolones. (a) Intramo...
Scheme 33: Hydrogen bonding/photocatalysed formal arylation of benzofuranones.
Scheme 34: Hydrogen bonding/photoredox-catalysed dehalogenative protonation of α,α-chlorofluoro ketones.
Scheme 35: Hydrogen bonding/photoredox-catalysed reductions. (a) Reduction of 1,2-diketones. (b) Reduction of ...
Scheme 36: Hydrogen bonding/HAT/photocatalysed deracemisation of cyclic ureas.
Scheme 37: Hydrogen bonding/HAT/photoredox-catalysed synthesis of cyclic sulfonamides.
Scheme 38: Hydrogen bonding/photoredox-catalysed reaction between imines and indoles.
Scheme 39: Chiral cation/photoredox-catalysed radical coupling of two α-amino radicals.
Scheme 40: Chiral phosphate/photoredox-catalysed hydroetherfication of alkenols.
Scheme 41: Chiral phosphate/photoredox-catalysed synthesis of pyrroloindolines.
Scheme 42: Chiral anion/photoredox-catalysed radical cation Diels–Alder reaction.
Scheme 43: Lewis acid/photoredox-catalysed cycloadditions of carbonyls. (a) Formal [2 + 2] cycloaddition of en...
Scheme 44: Lewis acid/photoredox-catalysed RCA reaction using a scandium Lewis acid between α-amino radicals a...
Scheme 45: Lewis acid/photoredox-catalysed RCA reaction using a copper Lewis acid between α-amino radicals and...
Scheme 46: Lewis acid/photoredox-catalysed synthesis of 1,2-amino alcohols from aldehydes and nitrones using a...
Scheme 47: Lewis acid/photocatalysed [2 + 2] photocycloadditions of enones and alkenes.
Scheme 48: Meggers’s chiral-at-metal catalysts.
Scheme 49: Lewis acid/photoredox-catalysed α-functionalisation of ketones with alkyl bromides bearing electron...
Scheme 50: Bifunctional Lewis acid/photoredox-catalysed radical coupling reaction using α-chloroketones and α-...
Scheme 51: Lewis acid/photocatalysed RCA of enones. (a) Using aldehydes as acyl radical precursors. (b) Other ...
Scheme 52: Bifunctional Lewis acid/photocatalysis for a photocycloaddition of enones.
Scheme 53: Lewis acid/photoredox-catalysed RCA reactions of enones using DHPs as radical precursors.
Scheme 54: Lewis acid/photoredox-catalysed functionalisation of β-ketoesters. (a) Hydroxylation reaction catal...
Scheme 55: Bifunctional copper-photocatalysed alkylation of imines.
Scheme 56: Copper/photocatalysed alkylation of imines. (a) Bifunctional copper catalysis using α-silyl amines....
Scheme 57: Bifunctional Lewis acid/photocatalysed intramolecular [2 + 2] photocycloaddition.
Scheme 58: Bifunctional Lewis acid/photocatalysed [2 + 2] photocycloadditions (a) Intramolecular cycloaddition...
Scheme 59: Bifunctional Lewis acid/photocatalysed rearrangement of 2,4-dieneones.
Scheme 60: Lewis acid/photocatalysed [2 + 2] cycloadditions of cinnamate esters and styrenes.
Scheme 61: Nickel/photoredox-catalysed arylation of α-amino acids using aryl bromides.
Scheme 62: Nickel/photoredox catalysis. (a) Desymmetrisation of cyclic meso-anhydrides using benzyl trifluorob...
Scheme 63: Nickel/photoredox catalysis for the acyl-carbamoylation of alkenes with aldehydes using TBADT as a ...
Scheme 64: Bifunctional copper/photoredox-catalysed C–N coupling between α-chloro amides and carbazoles or ind...
Scheme 65: Bifunctional copper/photoredox-catalysed difunctionalisation of alkenes with alkynes and alkyl or a...
Scheme 66: Copper/photoredox-catalysed decarboxylative cyanation of benzyl phthalimide esters.
Scheme 67: Copper/photoredox-catalysed cyanation reactions using TMSCN. (a) Propargylic cyanation (b) Ring ope...
Scheme 68: Palladium/photoredox-catalysed allylic alkylation reactions. (a) Using alkyl DHPs as radical precur...
Scheme 69: Manganese/photoredox-catalysed epoxidation of terminal alkenes.
Scheme 70: Chromium/photoredox-catalysed allylation of aldehydes.
Scheme 71: Enzyme/photoredox-catalysed dehalogenation of halolactones.
Scheme 72: Enzyme/photoredox-catalysed dehalogenative cyclisation.
Scheme 73: Enzyme/photoredox-catalysed reduction of cyclic imines.
Scheme 74: Enzyme/photocatalysed enantioselective reduction of electron-deficient alkenes as mixtures of (E)/(Z...
Scheme 75: Enzyme/photoredox catalysis. (a) Deacetoxylation of cyclic ketones. (b) Reduction of heteroaromatic...
Scheme 76: Enzyme/photoredox-catalysed synthesis of indole-3-ones from 2-arylindoles.
Scheme 77: Enzyme/HAT/photoredox catalysis for the DKR of primary amines.
Scheme 78: Bifunctional enzyme/photoredox-catalysed benzylic C–H hydroxylation of trifluoromethylated arenes.
Beilstein J. Org. Chem. 2020, 16, 2314–2321, doi:10.3762/bjoc.16.192
Graphical Abstract
Figure 1: Structures of electron-rich bis-macrocyclic host 1, and electron-poor guests bis(ammonium) 2, and b...
Figure 2: (a) Hunter’s 77 backbone-atom trefoil knot–metal complex [9]. (b) The world’s smallest knot: Leigh’s 7...
Figure 3: Schematic representation of the second-generation TLC approach to a 73 backbone atom trefoil knot.
Scheme 1: Two routes to azidobromide 6.
Scheme 2: Initial route to core diester 13. aLigand = tris(2-benzimidazolylmethyl)amine.
Scheme 3: Better yielding route to core diester 13. aLigand = tris(2-benzimidazolylmethyl)amine.
Scheme 4: Saponification of 13 and bis-macrocyclization to form host 1.
Scheme 5: Synthesis of 23 backbone-atom bis(ammonium) guest 2.
Scheme 6: Synthesis of 25 backbone-atom bis(pyridinium) guest 3.
Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183
Graphical Abstract
Figure 1: Fluorine-containing drugs.
Figure 2: Fluorinated agrochemicals.
Scheme 1: Selectivity of fluorination reactions.
Scheme 2: Different mechanisms of photocatalytic activation. Sub = substrate.
Figure 3: Jablonski diagram showing visible-light-induced energy transfer pathways: a) absorption, b) IC, c) ...
Figure 4: Schematic illustration of TTET.
Figure 5: Organic triplet PSCats.
Figure 6: Additional organic triplet PSCats.
Figure 7: A) Further organic triplet PSCats and B) transition metal triplet PSCats.
Figure 8: Different fluorination reagents grouped by generation.
Scheme 3: Synthesis of Selectfluor®.
Scheme 4: General mechanism of PS TTET C(sp3)–H fluorination.
Scheme 5: Selective benzylic mono- and difluorination using 9-fluorenone and xanthone PSCats, respectively.
Scheme 6: Chen’s photosensitized monofluorination: reaction scope.
Scheme 7: Chen’s photosensitized benzylic difluorination reaction scope.
Scheme 8: Photosensitized monofluorination of ethylbenzene on a gram scale.
Scheme 9: Substrate scope of Tan’s AQN-photosensitized C(sp3)–H fluorination.
Scheme 10: AQN-photosensitized C–H fluorination reaction on a gram scale.
Scheme 11: Reaction mechanism of the AQN-assisted fluorination.
Figure 9: 3D structures of the singlet ground and triplet excited states of Selectfluor®.
Scheme 12: Associated transitions for the activation of acetophenone by violet light.
Scheme 13: Ethylbenzene C–H fluorination with various PSCats and conditions.
Scheme 14: Effect of different PSCats on the C(sp3)–H fluorination of cyclohexane (39).
Scheme 15: Reaction scope of Chen’s acetophenone-photosensitized C(sp3)–H fluorination reaction.
Figure 10: a) Site-selectivity of Chen’s acetophenone-photosensitized C–H fluorination reaction [201]. b) Site-sele...
Scheme 16: Formation of the AQN–Selectfluor® exciplex Int1.
Scheme 17: Generation of the C3 2° pentane radical and the Selectfluor® N-radical cation from the exciplex.
Scheme 18: Hydrogen atom abstraction by the Selectfluor® N-radical cation from pentane to give the C3 2° penta...
Scheme 19: Fluorine atom transfer from Selectfluor® to the C3 2° pentane radical to yield 3-fluoropentane and ...
Scheme 20: Barrierless fluorine atom transfer from Int1 to the C3 2° pentane radical to yield 3-fluoropentane,...
Scheme 21: Ketone-directed C(sp3)–H fluorination.
Scheme 22: Ketone-directed fluorination through a 5- and a 6-membered transition state, respectively.
Scheme 23: Effect of different PSCats on the photosensitized C(sp3)–H fluorination of 47.
Scheme 24: Substrate scope of benzil-photoassisted C(sp3)–H fluorinations.
Scheme 25: A) Benzil-photoassisted enone-directed C(sp3)–H fluorination. B) Classification of the reaction mod...
Scheme 26: A) Xanthone-photoassisted ketal-directed C(sp3)–H fluorination. B) Substrate scope. C) C–H fluorina...
Scheme 27: Rationale for the selective HAT at the C2 C–H bond of galactose acetonide.
Scheme 28: Photosensitized C(sp3)–H benzylic fluorination of a peptide using different PSCats.
Scheme 29: Peptide scope of 5-benzosuberenone-photoassisted C(sp3)–H fluorinations.
Scheme 30: Continuous flow PS TTET monofluorination of 72.
Scheme 31: Photosensitized C–H fluorination of N-butylphthalimide as a PSX.
Scheme 32: Substrate scope and limitations of the PSX C(sp3)–H monofluorination.
Scheme 33: Substrate crossover monofluorination experiment.
Scheme 34: PS TTET mechanism proposed by Hamashima and co-workers.
Scheme 35: Photosensitized TFM of 78 to afford α-trifluoromethylated ketone 80.
Scheme 36: Substrate scope for photosensitized styrene TFM to give α-trifluoromethylated ketones.
Scheme 37: Control reactions for photosensitized TFM of styrenes.
Scheme 38: Reaction mechanism for photosensitized TFM of styrenes to afford α-trifluoromethylated ketones.
Scheme 39: Reaction conditions for TFMs to yield the cis- and the trans-product, respectively.
Scheme 40: Substrate scope of trifluoromethylated (E)-styrenes.
Scheme 41: Strategies toward trifluoromethylated (Z)-styrenes.
Scheme 42: Substrate scope of trifluoromethylated (Z)-styrenes.
Scheme 43: Reaction mechanism for photosensitized TFM of styrenes to afford E- or Z-products.
Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166
Graphical Abstract
Figure 1: Structures of spliceostatins/thailanstatins.
Scheme 1: Synthetic routes to protected (2Z,4S)-4-hydroxy-2-butenoic acid fragments.
Scheme 2: Kitahara synthesis of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 3: Koide synthesis of (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 4: Nicolaou synthesis of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 5: Jacobsen synthesis of the (all-cis)-2,3,5,6-tetrasubstituted tetrahydropyran.
Scheme 6: Unproductive attempt to generate the (all-cis)-tetrahydropyranone 50.
Scheme 7: Ghosh synthesis of the C-7–C-14 (all-cis)-tetrahydropyran segment.
Scheme 8: Ghosh’s alternative route to the (all-cis)-tetrahydropyranone 50.
Scheme 9: Alternative synthesis of the dihydro-3-pyrone 58.
Scheme 10: Kitahara’s 1st-generation synthesis of the C-1–C-6 fragment of FR901464 (1).
Scheme 11: Kitahara 1st-generation synthesis of the C-1–C-6 fragment of FR901464 (1).
Scheme 12: Nimura/Arisawa synthesis of the C-1-phenyl segment.
Scheme 13: Ghosh synthesis of the C-1–C-6 fragment of FR901464 (1) from (R)-glyceraldehyde acetonide.
Scheme 14: Jacobsen synthesis of the C-1–C-7 segment of FR901464 (1).
Scheme 15: Koide synthesis of the C-1–C-7 segment of FR901464 (1).
Scheme 16: Ghosh synthesis of the C-1–C-5 segment 102 of thailanstatin A (7).
Scheme 17: Nicolaou synthesis of the C-1–C-9 segments of spliceostatin D (9) and thailanstatins A (7) and B (5...
Scheme 18: Ghosh synthesis of the C-1–C-6 segment 115 of spliceostatin E (10).
Scheme 19: Fragment coupling via Wittig and modified Julia olefinations by Kitahara.
Scheme 20: Fragment coupling via cross-metathesis by Koide.
Scheme 21: The Ghosh synthesis of spliceostatin A (4), FR901464 (1), spliceostatin E (10), and thailanstatin m...
Scheme 22: Arisawa synthesis of a C-1-phenyl analog of FR901464 (1).
Scheme 23: Jacobsen fragment coupling by a Pd-catalyzed Negishi coupling.
Scheme 24: Nicolaou syntheses of thailanstatin A and B (7 and 5) and spliceostatin D (9) via a Pd-catalyzed Su...
Scheme 25: The Ghosh synthesis of spliceostatin G (11) via Suzuki–Miyaura coupling.
Beilstein J. Org. Chem. 2020, 16, 1936–1946, doi:10.3762/bjoc.16.160
Graphical Abstract
Figure 1: Representative fluorinated nucleos(t)ides and acyclonucleotides.
Figure 2: Acyclonucleotides as nucleotide surrogates.
Figure 3: Olefination approaches and ring-opening of oxetane derivatives.
Scheme 1: Preparation of fluoroakylidene-oxetanes and their ring-opening reactions.
Scheme 2: Synthesis of benzyloxy-substituted fluoroethylidene-oxetane derivative 8.
Scheme 3: Effect of the medium on the selective formation of derivative 10.
Scheme 4: Mechanism for the formation of dihydrofuran 10.
Scheme 5: Mechanism for the formation of unsaturated lactones 14 and 15.
Scheme 6: Opening reaction of ethyl 2-(oxetanyl-3-idene)acetate (16).
Scheme 7: Functionalization of bromomethyllactone 15 and its analogues.
Scheme 8: Functionalization by substitution reaction of the bromide E-1d vs ring-opening reaction of the oxet...
Scheme 9: Preparation of tetrasubstituted fluoroalkenes.
Beilstein J. Org. Chem. 2020, 16, 1627–1635, doi:10.3762/bjoc.16.135
Graphical Abstract
Figure 1: (A) Synthetic routes to α-fluoroketones from silyl enol ethers or acetophenone derivatives. (B) Sel...
Scheme 1: Substrate scope with standard reaction conditions: alkyne (0.2 mmol), p-TolI (20 mol %), Selectfluor...
Figure 2: X-ray molecular structure of compound 2. Conformation of the carbonyl group and the fluoride with a...
Figure 3: (A) Structure activity relationship of the core scaffold. (B) Exploring the effect of methyl benzoa...
Figure 4: (A) Hammett plot varying the para-substitution on the alkyne (ρ ≈ 0). (B) Hammett plot varying the ...
Figure 5: An overview of the I(I)/I(III)-catalysed fluorohydration of alkynes.
Beilstein J. Org. Chem. 2020, 16, 1296–1304, doi:10.3762/bjoc.16.110
Graphical Abstract
Figure 1: Phthalimide derivatives 1–3 and the corresponding azomethine ylides 1AMY-3AMY.
Scheme 1: Irradiation of 1 in the presence of acrylonitrile (AN).
Figure 2: Dependence of the chemical shift of the H-atom at the cyclohexane 2 position in compound 2 on the β...
Scheme 2: Complexation of 2 with β-CD, and formation of a ternary complex AN@2@β-CD.
Scheme 3: Photochemistry of 2 in the presence of AN, with or without β-CD.
Scheme 4: Photochemistry of 3 in the presence of AN, with or without β-CD.
Beilstein J. Org. Chem. 2020, 16, 1288–1295, doi:10.3762/bjoc.16.109
Graphical Abstract
Scheme 1: Synthesis of spirotetrahydrothiophenes 3 via non-concerted [3 + 2]-cycloadditions of thiocarbonyl y...
Scheme 2: Formal [3 + 2]-cycloadditions of thioketones and [4 + 3]-cycloadditions of thiochalcones with donor...
Scheme 3: Formal [3 + 2]-cycloadditions of dimethyl 2-substituted cyclopropane-1,1-dicarboxylates 5a–g with f...
Figure 1: Thermal ellipsoid plots of the molecular structures of cis-9c and trans-9d drawn using 50% probabil...
Scheme 4: Plausible mechanism for the formal [3 + 2]-cycloadditions of ferrocenyl thioketones 8 with D–A cycl...
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, 1022–1050, doi:10.3762/bjoc.16.91
Graphical Abstract
Figure 1: Categories I–V of fluorinated phenylalanines.
Scheme 1: Synthesis of fluorinated phenylalanines via Jackson’s method.
Scheme 2: Synthesis of all-cis-tetrafluorocyclohexylphenylalanines.
Scheme 3: Synthesis of ʟ-4-[sulfono(difluoromethyl)]phenylalanine (nPt: neopentyl, TCE: trichloroethyl).
Scheme 4: Synthesis of ʟ-4-[sulfono(difluoromethyl)]phenylalanine derivatives 17.
Scheme 5: Synthesis of fluorinated Phe analogues from Cbz-protected aminomalonates.
Scheme 6: Synthesis of tetrafluorophenylalanine analogues via the 3-methyl-4-imidazolidinone auxiliary 25.
Scheme 7: Synthesis of tetrafluoro-Phe derivatives via chiral auxiliary 31.
Scheme 8: Synthesis of 2,5-difluoro-Phe and 2,4,5-trifluoro-Phe via Schöllkopf reagent 34.
Scheme 9: Synthesis of 2-fluoro- and 2,6-difluoro Fmoc-Phe derivatives starting from chiral auxiliary 39.
Scheme 10: Synthesis of 2-[18F]FPhe via chiral auxiliary 43.
Scheme 11: Synthesis of FPhe 49a via photooxidative cyanation.
Scheme 12: Synthesis of FPhe derivatives via Erlenmeyer azalactone synthesis.
Scheme 13: Synthesis of (R)- and (S)-2,5-difluoro Phe via the azalactone method.
Scheme 14: Synthesis of 3-bromo-4-fluoro-(S)-Phe (65).
Scheme 15: Synthesis of [18F]FPhe via radiofluorination of phenylalanine with [18F]F2 or [18F]AcOF.
Scheme 16: Synthesis of 4-borono-2-[18F]FPhe.
Scheme 17: Synthesis of protected 4-[18F]FPhe via arylstannane derivatives.
Scheme 18: Synthesis of FPhe derivatives via intermediate imine formation.
Scheme 19: Synthesis of FPhe derivatives via Knoevenagel condensation.
Scheme 20: Synthesis of FPhe derivatives 88a,b from aspartic acid derivatives.
Scheme 21: Synthesis of 2-(2-fluoroethyl)phenylalanine derivatives 93 and 95.
Scheme 22: Synthesis of FPhe derivatives via Zn2+ complexes.
Scheme 23: Synthesis of FPhe derivatives via Ni2+ complexes.
Scheme 24: Synthesis of 3,4,5-trifluorophenylalanine hydrochloride (109).
Scheme 25: Synthesis of FPhe derivatives via phenylalanine aminomutase (PAM).
Scheme 26: Synthesis of (R)-2,5-difluorophenylalanine 115.
Scheme 27: Synthesis of β-fluorophenylalanine via 2-amino-1,3-diol derivatives.
Scheme 28: Synthesis of β-fluorophenylalanine derivatives via the oxazolidinone chiral auxiliary 122.
Scheme 29: Synthesis of β-fluorophenylalanine from pyruvate hemiketal 130.
Scheme 30: Synthesis of β-fluorophenylalanine (136) via fluorination of β-hydroxyphenylalanine (137).
Scheme 31: Synthesis of β-fluorophenylalanine from aziridine derivatives.
Scheme 32: Synthesis of β-fluorophenylalanine 136 via direct fluorination of pyruvate esters.
Scheme 33: Synthesis of β-fluorophenylalanine via fluorination of ethyl 3-phenylpyruvate enol using DAST.
Scheme 34: Synthesis of β-fluorophenylalanine derivatives using photosensitizer TCB.
Scheme 35: Synthesis of β-fluorophenylalanine derivatives using Selectflour and dibenzosuberenone.
Scheme 36: Synthesis of protected β-fluorophenylalanine via aziridinium intermediate 150.
Scheme 37: Synthesis of β-fluorophenylalanine derivatives via fluorination of α-hydroxy-β-aminophenylalanine d...
Scheme 38: Synthesis of β-fluorophenylalanine derivatives from α- or β-hydroxy esters 152a and 155.
Scheme 39: Synthesis of a series of β-fluoro-Phe derivatives via Pd-catalyzed direct fluorination of β-methyle...
Scheme 40: Synthesis of series of β-fluorinated Phe derivatives using quinoline-based ligand 162 in the Pd-cat...
Scheme 41: Synthesis of β,β-difluorophenylalanine derivatives from 2,2-difluoroacetaldehyde derivatives 164a,b....
Scheme 42: Synthesis of β,β-difluorophenylalanine derivatives via an imine chiral auxiliary.
Scheme 43: Synthesis of α-fluorophenylalanine derivatives via direct fluorination of protected Phe 174.
Figure 2: Structures of PET radiotracers of 18FPhe derivatives.
Figure 3: Structures of melfufen (179) and melphalan (180) anticancer drugs.
Figure 4: Structure of gastrazole (JB95008, 181), a CCK2 receptor antagonist.
Figure 5: Dual CCK1/CCK2 antagonist 182.
Figure 6: Structure of sitagliptin (183), an antidiabetic drug.
Figure 7: Structure of retaglpitin (184) and antidiabetic drug.
Figure 8: Structure of evogliptin (185), an antidiabetic drug.
Figure 9: Structure of LY2497282 (186) a DPP-4 inhibitor for the treatment of type II diabetes.
Figure 10: Structure of ulimorelin (187).
Figure 11: Structure of GLP1R (188).
Figure 12: Structures of Nav1.7 blockers 189 and 190.
Beilstein J. Org. Chem. 2020, 16, 451–481, doi:10.3762/bjoc.16.42
Graphical Abstract
Scheme 1: [Cu(I)(dap)2]Cl-catalyzed ATRA reaction under green light irradiation.
Scheme 2: Photocatalytic allylation of α-haloketones.
Scheme 3: [Cu(I)(dap)2]Cl-photocatalyzed chlorosulfonylation and chlorotrifluoromethylation of alkenes.
Scheme 4: Photocatalytic perfluoroalkylchlorination of electron-deficient alkenes using the Sauvage catalyst.
Scheme 5: Photocatalytic synthesis of fluorinated sultones.
Scheme 6: Photocatalyzed haloperfluoroalkylation of alkenes and alkynes.
Scheme 7: Chlorosulfonylation of alkenes catalyzed by [Cu(I)(dap)2]Cl. aNo Na2CO3 was added. b1 equiv of Na2CO...
Scheme 8: Copper-photocatalyzed reductive allylation of diaryliodonium salts.
Scheme 9: Copper-photocatalyzed azidomethoxylation of olefins.
Scheme 10: Benzylic azidation initiated by [Cu(I)(dap)2]Cl.
Scheme 11: Trifluoromethyl methoxylation of styryl derivatives using [Cu(I)(dap)2]PF6. All redox potentials ar...
Scheme 12: Trifluoromethylation of silyl enol ethers.
Scheme 13: Synthesis of annulated heterocycles upon oxidation with the Sauvage catalyst.
Scheme 14: Oxoazidation of styrene derivatives using [Cu(dap)2]Cl as a precatalyst.
Scheme 15: [Cu(I)(dpp)(binc)]PF6-catalyzed ATRA reaction.
Scheme 16: Allylation reaction of α-bromomalonate catalyzed by [Cu(I)(dpp)(binc)]PF6 following an ATRA mechani...
Scheme 17: Bromo/tribromomethylation reaction using [Cu(I)(dmp)(BINAP)]PF6.
Scheme 18: Chlorotrifluoromethylation of alkenes catalyzed by [Cu(I)(N^N)(xantphos)]PF6.
Scheme 19: Chlorosulfonylation of styrene and alkyne derivatives by ATRA reactions.
Scheme 20: Reduction of aryl and alkyl halides with the complex [Cu(I)(bcp)(DPEPhos)]PF6. aIrradiation was car...
Scheme 21: Meerwein arylation of electron-rich aromatic derivatives and 5-exo-trig cyclization catalyzed by th...
Scheme 22: [Cu(I)(bcp)(DPEPhos)]PF6-photocatalyzed synthesis of alkaloids. aYield over two steps (cyclization ...
Scheme 23: Copper-photocatalyzed decarboxylative amination of NHP esters.
Scheme 24: Photocatalytic decarboxylative alkynylation using [Cu(I)(dq)(binap)]BF4.
Scheme 25: Copper-photocatalyzed alkylation of glycine esters.
Scheme 26: Copper-photocatalyzed borylation of organic halides. aUnder continuous flow conditions.
Scheme 27: Copper-photocatalyzed α-functionalization of alcohols with glycine ester derivatives.
Scheme 28: δ-Functionalization of alcohols using [Cu(I)(dmp)(xantphos)]BF4.
Scheme 29: Photocatalytic synthesis of [5]helicene and phenanthrene.
Scheme 30: Oxidative carbazole synthesis using in situ-formed [Cu(I)(dmp)(xantphos)]BF4.
Scheme 31: Copper-photocatalyzed functionalization of N-aryl tetrahydroisoquinolines.
Scheme 32: Bicyclic lactone synthesis using a copper-photocatalyzed PCET reaction.
Scheme 33: Photocatalytic Pinacol coupling reaction catalyzed by [Cu(I)(pypzs)(BINAP)]BF4. The ligands of the ...
Scheme 34: Azide photosensitization using a Cu-based photocatalyst.
Beilstein J. Org. Chem. 2019, 15, 2509–2523, doi:10.3762/bjoc.15.244
Graphical Abstract
Figure 1: Design of the CXCR3 efficacy photowitchable ligands. A,B) Schematic representation of a GPCR photoc...
Figure 2: Conformational alignment of a biaryl CXCR3 agonist with a designed azobenzene analogue. A) 2D struc...
Scheme 1: Synthetic strategies for compounds 2a–e, 3a–e, 4a–d, 4f–i and 5b,c (Y = H, Cl). Reagents and condit...
Scheme 2: Synthetic strategies for compounds 3f–h, 4e, 6b, and 6d (Y = H, F, Cl, Br). Reagents and conditions...
Figure 3: Comparison of compounds belonging to the subseries 3 or 4 with a halogen substitution on the ortho-...
Scheme 3: Synthetic strategy for compound 6e. Reagents and conditions: (a) i) K2CO3 (2.0 equiv), DMF, µW, 65 ...
Scheme 4: Synthetic strategies for compounds 6f–h (Y = OMe, OiPr, SMe). Reagents and conditions: (a) NaOMe or...
Figure 4: Properties of subseries 3e, 4d, 6b and 6d-h. (A) UV–vis absorption spectra of (top) trans-isomers o...
Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218
Graphical Abstract
Scheme 1: The main three strategies of fluorination: nucleophilic, electrophilic and radical fluorination.
Scheme 2: Doyle’s Pd-catalyzed fluorination of allylic chlorides.
Scheme 3: Allylic fluorination of 2- and 3-substituted propenyl esters.
Scheme 4: Regioselective allylic fluorination of cinnamyl phosphorothioate esters.
Scheme 5: Palladium-catalyzed aliphatic C–H fluorination reported by Doyle.
Scheme 6: Pd-catalyzed enantioselective fluorination of α-ketoesters followed by stereoselective reduction to...
Scheme 7: Pd-catalyzed C(sp3)–H fluorination of oxindoles.
Scheme 8: C–H fluorination of 8-methylquinoline derivatives with F− reagents.
Scheme 9: Fluorination of α-cyano acetates reported by van Leeuwen.
Scheme 10: The catalytic enantioselective electrophilic C–H fluorination of α-chloro-β-keto phosphonates.
Scheme 11: Fluorination of unactivated C(sp3)–H bonds directed by the bidentate PIP auxiliary.
Scheme 12: Fluorination of C(sp3)–H bonds at the β-position of carboxylic acids.
Scheme 13: Enantioselective benzylic C–H fluorination with a chiral transient directing group.
Scheme 14: Microwave-heated Pd-catalyzed fluorination of aryl alcohols.
Scheme 15: Fluorination of aryl potassium trifluoroborates.
Scheme 16: C(sp2)–F bond formation using precatalyst [L·Pd]2(cod).
Scheme 17: Pd-catalyzed fluorination of (hetero)aryl triflates and bromides.
Scheme 18: The Pd-catalyzed C–H fluorination of arenes with Selectfluor/NFSI.
Scheme 19: Pd(II)-catalyzed ortho-monofluorination protocol for benzoic acids.
Scheme 20: Pd-catalyzed C(sp2)–H bond fluorination of 2-arylbenzothiazoles.
Scheme 21: Nitrate-promoted fluorination of aromatic and olefinic C(sp2)–H bonds and proposed mechanism.
Scheme 22: Fluorination of oxalyl amide-protected benzylamine derivatives.
Scheme 23: C–H fluorination of benzaldehydes with orthanilic acids as transient directing group.
Scheme 24: Pd(II)-catalyzed aryl C–H fluorination with various directing groups.
Scheme 25: Cu-catalyzed aliphatic, allylic, and benzylic fluorination.
Scheme 26: Cu-catalyzed SN2 fluorination of primary and secondary alkyl bromides.
Scheme 27: Copper-catalyzed fluorination of alkyl triflates.
Scheme 28: Cu-catalyzed fluorination of allylic bromides and chlorides.
Scheme 29: Synthetic strategy for the fluorination of active methylene compounds.
Scheme 30: Fluorination of β-ketoesters using a tartrate-derived bidentate bisoxazoline-Cu(II) complex.
Scheme 31: Highly enantioselective fluorination of β-ketoesters and N-Boc-oxindoles.
Scheme 32: Amide group-assisted site-selective fluorination of α-bromocarbonyl compounds.
Scheme 33: Cu-mediated aryl fluorination reported by Sanford [77].
Scheme 34: Mono- or difluorination reactions of benzoic acid derivatives.
Scheme 35: Cu-catalyzed fluorination of diaryliodonium salts with KF.
Scheme 36: Copper(I)-catalyzed cross-coupling of 2-pyridylaryl bromides.
Scheme 37: AgNO3-catalyzed decarboxylative fluorination of aliphatic carboxylic acids.
Scheme 38: The Mn-catalyzed aliphatic and benzylic C–H fluorination.
Scheme 39: Iron(II)-promoted C–H fluorination of benzylic substrates.
Scheme 40: Ag-catalyzed fluorodecarboxylation of carboxylic acids.
Scheme 41: Vanadium-catalyzed C(sp3)–H fluorination.
Scheme 42: AgNO3-catalyzed radical deboronofluorination of alkylboronates and boronic acids.
Scheme 43: Selective heterobenzylic C–H fluorination with Selectfluor reported by Van Humbeck.
Scheme 44: Fe(II)-catalyzed site-selective fluorination guided by an alkoxyl radical.
Scheme 45: Fluorination of allylic trichloroacetimidates reported by Nguyen et al.
Scheme 46: Iridium-catalyzed fluorination of allylic carbonates with TBAF(t-BuOH)4.
Scheme 47: Iridium-catalyzed asymmetric fluorination of allylic trichloroacetimidates.
Scheme 48: Cobalt-catalyzed α-fluorination of β-ketoesters.
Scheme 49: Nickel-catalyzed α-fluorination of various α-chloro-β-ketoesters.
Scheme 50: Ni(II)-catalyzed enantioselective fluorination of oxindoles and β-ketoesters.
Scheme 51: Scandium(III)-catalyzed asymmetric C–H fluorination of unprotected 3-substituted oxindoles.
Scheme 52: Iron-catalyzed directed C–H fluorination.
Scheme 53: Electrophilic silver-catalyzed Ar–F bond-forming reaction from arylstannanes.
Figure 1: Nucleophilic, electrophilic and radical CF3 sources.
Scheme 54: Cu(I)-catalyzed allylic trifluoromethylation of unactivated terminal olefins.
Scheme 55: Direct copper-catalyzed trifluoromethylation of allylsilanes.
Scheme 56: Cupper-catalyzed enantioselective trifluoromethylation of five and six-membered ring β-ketoesters.
Scheme 57: Cu-catalyzed highly stereoselective trifluoromethylation of secondary propargyl sulfonates.
Scheme 58: Remote C(sp3)–H trifluoromethylation of carboxamides and sulfonamides.
Scheme 59: Trifluoromethylation of allylsilanes with photoredox catalysis.
Scheme 60: Ag-catalyzed decarboxylative trifluoromethylation of aliphatic carboxylic acids in aqueous CH3CN.
Scheme 61: Decarboxylative trifluoromethylation of aliphatic carboxylic acids via combined photoredox and copp...
Scheme 62: Palladium-catalyzed Ar–CF3 bond-forming reaction.
Scheme 63: Palladium-catalyzed trifluoromethylation of arenes with diverse heterocyclic directing groups.
Scheme 64: Pd-catalyzed trifluoromethylation of indoles as reported by Liu.
Scheme 65: Pd-catalyzed trifluoromethylation of vinyl triflates and vinyl nonaflates.
Scheme 66: Pd(II)-catalyzed ortho-trifluoromethylation of aromatic C–H bonds.
Scheme 67: Visible-light-induced Pd(OAc)2-catalyzed ortho-trifluoromethylation of acetanilides with CF3SO2Na.
Scheme 68: CuI-catalyzed trifluoromethylation of aryl- and alkenylboronic acids.
Scheme 69: Cu-catalyzed trifluoromethylation of aryl- and vinylboronic acids.
Scheme 70: Copper-catalyzed trifluoromethylation of α,β-unsaturated carboxylic acids.
Scheme 71: Formation of C(sp2)–CF3 bond catalyzed by copper(I) complex.
Scheme 72: Loh’s Cu(I)-catalyzed trifluoromethylation of enamides and electron-deficient alkenes.
Scheme 73: Copper and iron-catalyzed decarboxylative tri- and difluoromethylation.
Scheme 74: Cu-catalyzed trifluoromethylation of hydrazones developed by Bouyssi.
Scheme 75: Cu(I)-catalyzed trifluoromethylation of terminal alkenes.
Scheme 76: Cu/Ag-catalyzed decarboxylative trifluoromethylation of cinnamic acids.
Scheme 77: Copper-catalyzed direct alkenyl C–H trifluoromethylation.
Scheme 78: Copper(I/II)-catalyzed direct trifluoromethylation of styrene derivatives.
Scheme 79: Regioselective trifluoromethylation of pivalamido arenes and heteroarenes.
Scheme 80: Synthesis of trifluoromethylquinones in the presence of copper(I).
Scheme 81: Oxidative trifluoromethylation of imidazoheterocycles in ionic liquid/water.
Scheme 82: A mild and fast continuous-flow trifluoromethylation of coumarins using a CuI/CF3SO2Na/TBHP system.
Scheme 83: Copper-catalyzed oxidative trifluoromethylation of various 8-aminoquinolines.
Scheme 84: PA-directed copper-catalyzed trifluoromethylation of anilines.
Scheme 85: Trifluoromethylation of potassium vinyltrifluoroborates catalyzed by Fe(II).
Scheme 86: Alkenyl trifluoromethylation catalyzed by Ru(phen)3Cl2 as photocatalyst.
Scheme 87: Ru-catalyzed trifluoromethylation of alkenes by Akita’s group.
Scheme 88: Ir-catalyzed Cvinyl–CF3 bond formation of α,β-unsaturated carboxylic acids.
Scheme 89: Ag(I)-catalyzed denitrative trifluoromethylation of β-nitrostyrenes.
Scheme 90: Photocatalyzed direct trifluoromethylation of aryl and heteroaryl C–H bonds.
Scheme 91: Rhenium (MTO)-catalyzed direct trifluoromethylation of aromatic substrates.
Scheme 92: Trifluoromethylation of unprotected anilines under [Ir(ppy)3] catalyst.
Scheme 93: Oxidative trifluoromethylation of imidazopyridines and imidazoheterocycles.
Scheme 94: Ruthenium-catalyzed trifluoromethylation of (hetero)arenes with trifluoroacetic anhydride.
Scheme 95: Phosphovanadomolybdic acid-catalyzed direct C–H trifluoromethylation.
Scheme 96: Picolinamide-assisted ortho-trifluoromethylation of arylamines.
Scheme 97: A nickel-catalyzed C–H trifluoromethylation of free anilines.
Scheme 98: Cu-mediated trifluoromethylation of terminal alkynes reported by Qing.
Scheme 99: Huang’s C(sp)–H trifluoromethylation using Togni’s reagent.
Scheme 100: Cu-catalyzed methods for trifluoromethylation with Umemoto’s reagent.
Scheme 101: The synthesis of alkynyl-CF3 compounds in the presence of fac-[Ir(ppy)3] under visible-light irradi...
Scheme 102: Pd-catalyzed Heck reaction reported by Reutrakul.
Scheme 103: Difluoromethylation of enamides and ene-carbamates.
Scheme 104: Difluoromethylation of α,β-unsaturated carboxylic acids.
Scheme 105: Copper-catalyzed direct C(sp2)–H difluoroacetylation reported by Pannecoucke and co-workers.
Scheme 106: Difluoroalkylation of aldehyde-derived hydrazones with functionalized difluoromethyl bromides.
Scheme 107: Photoredox-catalyzed C–H difluoroalkylation of aldehyde-derived hydrazones.
Scheme 108: Synergistic ruthenium(II)-catalyzed C–H difluoromethylation reported by Ackermann.
Scheme 109: Visible-light photocatalytic decarboxylation of α,β-unsaturated carboxylic acids.
Scheme 110: Synthesis of difluorinated ketones via S-alkyl dithiocarbamates obtained from acyl chlorides and po...
Scheme 111: Synthesis of aryl and heteroaryl difluoromethylated phosphonates.
Scheme 112: Difluoroalkylation of secondary propargyl sulfonates using Cu as the catalyst.
Scheme 113: Ru(II)-mediated para-selective difluoromethylation of anilides and their derivatives.
Scheme 114: Bulky diamine ligand promoted cross-coupling of difluoroalkyl bromides.
Scheme 115: Copper-catalyzed C3–H difluoroacetylation of quinoxalinones.
Scheme 116: Copper(I) chloride-catalyzed trifluoromethylthiolation of enamines, indoles and β-ketoesters.
Scheme 117: Copper-boxmi-catalyzed asymmetric trifluoromethylthiolation of β-ketoesters.
Scheme 118: Direct Cu-catalyzed trifluoromethylthiolation of boronic acids and alkynes.
Scheme 119: Cu-catalyzed synthesis of α-trifluoromethylthio-substituted ketones.
Scheme 120: Trifluoromethylthiolation reactions promoted by diazotriflone and copper.
Scheme 121: Halide activation of N-(trifluoromethylthio)phthalimide.
Scheme 122: The visible light-promoted trifluoromethylthiolation reported by Glorius.
Scheme 123: Synthesis of α-trifluoromethylthioesters via Goossen’s approach.
Scheme 124: Photoinduced trifluoromethylthiolation of diazonium salts.
Scheme 125: Ag-mediated trifluoromethoxylation of aryl stannanes and arylboronic acids.
Scheme 126: Catalytic (hetero)aryl C–H trifluoromethoxylation under visible light.
Scheme 127: Photoinduced C–H-bond trifluromethoxylation of (hetero)arenes.
Beilstein J. Org. Chem. 2019, 15, 1976–1983, doi:10.3762/bjoc.15.193
Graphical Abstract
Scheme 1: Synthesis of phthalimide-containing O6-corona[3]arene[3]tetrazines.
Figure 1: X-ray molecular structure of 3a (CCDC 1913907) with side (left) and top (right) views. All solvent ...
Figure 2: 1H (top) and 13C (bottom) NMR spectra of 3a in acetone-d6 at 25 °C.
Figure 3: Normalized cyclic voltammograms (left) and differential pulse voltammograms (right) of 3a. CV and D...
Figure 4: X-ray molecular structures of complexes (n-Bu4NCl)3-3a (1913908) (top) and (n-Bu4NBr)3-3a (1913909)...
Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104
Graphical Abstract
Figure 1: γ-Lactam-derived structures considered in this review.
Figure 2: Alkaloids containing an isoindolinone moiety.
Figure 3: Alkaloids containing the 2-oxindole ring system.
Figure 4: Drugs and biological active compounds containing an isoindolinone moiety.
Figure 5: Drugs and biologically active compounds bearing a 2-oxindole skeleton.
Scheme 1: Three-component reaction of benzoic acid 1, amides 2 and DMSO (3).
Scheme 2: Copper-catalysed three-component reaction of 2-iodobenzoic acids 10, alkynylcarboxylic acids 11 and...
Scheme 3: Proposed mechanism for the formation of methylene isoindolinones 13.
Scheme 4: Copper-catalysed three-component reaction of 2-iodobenzamide 17, terminal alkyne 18 and pyrrole or ...
Scheme 5: Palladium-catalysed three-component reaction of ethynylbenzamides 21, secondary amines 22 and CO (23...
Scheme 6: Proposed mechanism for the formation of methyleneisoindolinones 24.
Scheme 7: Copper-catalysed three-component reaction of formyl benzoate 29, amines 2 and alkynes 18.
Scheme 8: Copper-catalysed three-component reaction of formylbenzoate 29, amines 2 and ketones 31.
Scheme 9: Non-catalysed (A) and phase-transfer catalysed (B) three-component reactions of formylbenzoic acids ...
Scheme 10: Proposed mechanism for the formation of isoindolinones 36.
Scheme 11: Three-component reaction of formylbenzoic acid 33, amines 2 and fluorinated silyl ethers 39.
Scheme 12: Three-component Ugi reaction of 2-formylbenzoic acid (33), diamines 41 and isocyanides 42.
Scheme 13: Non-catalysed (A, B) and chiral phosphoric acid promoted (C) three-component Ugi reactions of formy...
Scheme 14: Proposed mechanism for the enantioselective formation of isoindolinones 46.
Scheme 15: Three-component reaction of benzoic acids 33 or 54, amines 2 and TMSCN (52).
Scheme 16: Several variations of the three-component reaction of formylbenzoic acids 33, amines 2 and isatoic ...
Scheme 17: Proposed mechanism for the synthesis of isoindoloquinazolinones 57.
Scheme 18: Three-component reaction of isobenzofuranone 61, amines 2 and isatoic anhydrides 56.
Scheme 19: Palladium-catalysed three-component reaction of 2-aminobenzamides 59, 2-bromobenzaldehydes 62 and C...
Scheme 20: Proposed mechanism for the palladium-catalysed synthesis of isoindoloquinazolinones 57.
Scheme 21: Four-component reaction of 2-vinylbenzoic acids 67, aryldioazonium tetrafluoroborates 68, DABCO·(SO2...
Scheme 22: Plausible mechanism for the formation of isoindolinones 71.
Scheme 23: Three-component reaction of trimethylsilylaryltriflates 77, isocyanides 42 and CO2 (78).
Scheme 24: Plausible mechanism for the three-component synthesis of phthalimides 79.
Scheme 25: Copper-catalysed three-component reaction of 2-formylbenzonitriles 85, arenes 86 and diaryliodonium...
Scheme 26: Copper-catalysed three-component reaction of 2-formylbenzonitriles 85, diaryliodonium salts 87 and ...
Scheme 27: Proposed mechanism for the formation of 2,3-diarylisoindolinones 88, 89 and 92.
Scheme 28: Palladium-catalysed three-component reaction of chloroquinolinecarbaldehydes 97 with isocyanides 42...
Scheme 29: Palladium-catalysed three-component reaction of imines 99 with CO (23) and ortho-iodoarylimines 100....
Scheme 30: Palladium-catalysed three-component reaction of amines 2 with CO (23) and aryl iodide 105.
Scheme 31: Three-component reaction of 2-ethynylanilines 109, perfluoroalkyl iodides 110 and carbon monoxide (...
Scheme 32: Ultraviolet-induced three-component reaction of N-(2-iodoaryl)acrylamides 113, DABCO·(SO2)2 (69) an...
Scheme 33: Proposed mechanism for the preparation of oxindoles 115.
Scheme 34: Three-component reaction of acrylamide 113, CO (23) and 1,4-benzodiazepine 121.
Scheme 35: Multicomponent reaction of sulfonylacrylamides 123, aryldiazonium tetrafluoroborates 68 and DABCO·(...
Scheme 36: Proposed mechanism for the preparation of oxindoles 124.
Scheme 37: Three-component reaction of N-arylpropiolamides 128, aryl iodides 129 and boronic acids 130.
Scheme 38: Proposed mechanism for the formation of diarylmethylene- and diarylallylideneoxindoles 131 and 132.
Scheme 39: Three-component reaction of cyclohexa-1,3-dione (136), amines 2 and alkyl acetylenedicarboxylates 1...
Scheme 40: Proposed mechanism for the formation of 2-oxindoles 138.
Beilstein J. Org. Chem. 2019, 15, 818–829, doi:10.3762/bjoc.15.79
Graphical Abstract
Figure 1: Conformations of cis-2-halocyclohexylamines, where X = F, Cl, Br and I.
Figure 2: Variable-temperature 1H NMR spectra (500.13 MHz) for cis-2-chlorocyclohexylamine in dichloromethane-...
Figure 3: Potential energy surfaces (PESs) for cis-2-halocyclohexylamines for the C2–C1–N–H dihedral angle ro...
Figure 4: Populations of rotamers a, gX e gH in ae (top) and ea (bottom) conformers of cis-2-halocyclohexylam...
Figure 5: Nitrogen lone pair in rotamers gX (ae) and a (ea) oriented towards the halogen, making these rotame...
Figure 6: PCA for 22 variables corresponding to the hyperconjugative interactions for all rotamers in ae and ...
Figure 7: Sum of bonding (donor) and antibonding (acceptor) orbitals interactions of C1–H, C2–X and C3–Hax bo...
Figure 8: Orbitals overlap of σC1–H → σ*C2–X (left) and σC3–Hax → σ*C2–X (right) hyperconjugations in ea conf...
Beilstein J. Org. Chem. 2019, 15, 602–609, doi:10.3762/bjoc.15.55
Graphical Abstract
Figure 1: Catalyst optimization for the monooxidation of n-butylbenzene mediated by the iodate anion.
Figure 2: NHPI-catalyzed oxidation of secondary benzylic C–H bonds mediated by iodine(V). a100 °C for 18 h; b...
Figure 3: NHPI-catalyzed oxidation of di-benzylic C–H bonds mediated by iodate.
Figure 4: NHPI-catalyzed oxidation of substrates containing primary and tertiary benzylic C–H bonds. aReactio...
Figure 5: Competitive deuterium KIE for the oxidation of ethyl benzene by the NHPI-iodate system.
Figure 6: Pyrolysis of an acyl perester in the presence of molecular iodine.
Figure 7: Proposed mechanism for the selective monooxygenation of benzylic C–H bonds.
Beilstein J. Org. Chem. 2019, 15, 535–541, doi:10.3762/bjoc.15.47
Graphical Abstract
Scheme 1: General procedure for the synthesis of nematophin and related derivatives. i) 1.5 equiv α-keto carb...
Scheme 2: Synthesis of azatryptamines (4-azatryptamine (4ATRA) and 1-methyl-4-azatryptamine (1M4ATRA)). i) 5....
Scheme 3: Synthesis of azatryptamines (7-azatryptamine (7ATRA) and 1-methyl-7-azatryptamine (1M7ATRA)). i) 5....
Beilstein J. Org. Chem. 2018, 14, 2829–2837, doi:10.3762/bjoc.14.261
Graphical Abstract
Figure 1: Schematic representation of native α-CD (1) and top view of its primary rim with alphabetic clockwi...
Scheme 1: Synthesis of 6A,6X-diazido-α-CD derivatives 4 via 6A,6X-capped α-CDs 2 and 3 and their regioisomeri...
Scheme 2: Synthesis of 6A,6X- and 6A,6D-diazido-α-CDs via 6A,6X-dibromo-α-CD 5, 6A,6D-dibromo-α-CD 5d interme...
Scheme 3: Synthesis of 6A,6X-diazido-α-CDs via 6A,6X-ditosyl-α-CD intermediates 6 and their regioisomeric rat...
Figure 2: HPLC chromatograms of 6A,6X-diazido-α-CDs 4 of the reactions 1–5, with ACN/water gradient elution a...
Scheme 4: Synthesis of 6A-azido-6X-mesitylenesulfonyl-α-CD 8 and conversion into 6A,6X-diazido-α-CD 4.
Figure 3: HPLC chromatograms of reaction 7 with separated 6A-azido-α-CD 7 as starting material and regioisome...
Figure 4: HPLC chromatograms of 6A-azido-6X-mesitylenesulfonyl-α-CD 8 (reaction 6): a) analytical and b) prep...
Figure 5: 1H NMR spectrum of the AC regioisomer 8c as a mixture of pseudoenantiomers prepared through reactio...
Figure 6: 13C NMR spectrum of the AC regioisomer 8c as a mixture of pseudoenantiomers prepared through reacti...
Figure 7: HPLC–MS chromatogram with the separated pseudoenantiomers of 6A-azido-6B-mesitylenesulfonyl-α-CD 8b...
Beilstein J. Org. Chem. 2018, 14, 2822–2828, doi:10.3762/bjoc.14.260
Graphical Abstract
Figure 1: Structures of hamamelitannin (1), lead compound 2 and target compounds 3.
Scheme 1: Proposed strategy for the synthesis of the target analogues.
Scheme 2: Synthesis of fragment 9. Reagents and conditions: a) phthalimide, Pd2(allyl)2Cl2, ligand 15, Na2CO3...
Scheme 3: Synthesis of fragment 10. Reagents and conditions: a) TBSCl, NaH, THF, rt; b) phthalimide, PPh3, DE...
Scheme 4: Coupling of 9 and 10 and attempted ring-closing metathesis. Reagents and conditions: a) PPh3, DEAD,...
Scheme 5: Synthesis of alternative eastern fragment 23. Reagents and conditions: a) TBSCl, imidazole, CH2Cl2,...
Scheme 6: Synthesis of 4. Reagents and conditions: a) PPh3, DEAD, THF, 0 °C to rt; b) Grubbs–Hoveyda II (5 mo...
Scheme 7: Late stage functionalization of the pyrrolidine nitrogen. Reagents and conditions: A) (masked) alde...
Figure 2: Molecular X-ray structure of 3a, showing thermal displacement ellipsoids at the 50% probability lev...