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Search for "disulfide" in Full Text gives 186 result(s) in Beilstein Journal of Organic Chemistry.
Ratiometric fluorescent probe for enantioselective detection of D-cysteine in aqueous solution
- Xiao-bo Zhou,
- Wing-Hong Chan,
- Albert W. M. Lee and
- Chi-Chung Yeung
Beilstein J. Org. Chem. 2011, 7, 1508–1515, doi:10.3762/bjoc.7.176
- ]. The facile cyclization of β- or γ-aminothiols with aldehydes containing fluorescent probes forms the basis for the development of several fluorescent probes [12][13][14][15][16][17]. In addition, cleavage of disulfide-based probes by thiols [18][19][20][21] and other thiol-sensing tactics have been
Graphical Abstract
Figure 1: Structures of biological active thiols.
Figure 2: The structure of ACAQ.
Figure 3: Emission spectra of (a) Zn2+–ACAQ or (b) Cd2+–ACAQ complex (5 μM) at increasing concentrations of C...
Figure 4: Job’s plot of Cd2+–ACAQ in 10 mM HEPES buffer (pH 7.4) at 298 K. The sum of the concentrations of t...
Figure 5: Fluorescence spectra of Cd2+–ACAQ (10 µm) upon the titration of (a) D-Cys and (b) L-Cys in buffer s...
Figure 6: Fluoresence emission change of Cd2+–ACAQ at 500 nm in response to the addition of 15 equiv amino ac...
Figure 7: Fluorescence spectra of (10 µm) Cd2+–ACAQ upon the titration of various amino acids in buffer solut...
Figure 8: UV spectra of Cd2+–ACAQ (25 µm) upon the titration of (a) D-Cys, (b) L-Cys (0–12 equiv) in buffer s...
Figure 9: Partial 1H NMR spectra (400 MHz) of ACAQ (5 mM) before and after the addition of Cd2+ and then incr...
Figure 10: Proposed binding model of Cd2+–ACAQ with cysteine.
Figure 11: Reversibility study. Emission spectra of Cd2+–ACAQ complex (5 μM) with 10 equiv L-Cys in buffer sol...
Advances in synthetic approach to and antifungal activity of triazoles
- Kumari Shalini,
- Nitin Kumar,
- Sushma Drabu and
- Pramod Kumar Sharma
Beilstein J. Org. Chem. 2011, 7, 668–677, doi:10.3762/bjoc.7.79
- , phenoxyacetic acid derivatives and carbon disulfide, respectively. Their antifungal activity was investigated against Aspergillus niger and Fusarium oxysporum. Among the series of synthesized compounds, 7-(3-chlorophenyl)-6,7-dihydro-5H-imidazo[2,1-c][1,2,4]triazole-3-thiol (8, Figure 6) showed the most
Graphical Abstract
Figure 1: Isomeric forms of triazole.
Scheme 1: Copper catalyzed azide–alkyne cycloaddition.
Scheme 2: Ruthenium catalyzed azide–alkyne cycloaddition.
Scheme 3: Copper-sulfate catalyzed azide–alkyne cycloaddition.
Scheme 4: Azide–dimethylbut-2-yne-dioate cycloaddition.
Figure 2: Triazole compound 3 with most potent antifugal activity against various strains [20].
Figure 3: Triazole compounds 4 and 5 showing antifungal activity against Candida albicans [31].
Figure 4: Triazole compound 6 with the highest activity against Aspergillus flavus, Aspergillus versicolor, A...
Figure 5: Triazole compound 7 exhibiting an MIC of 25 µg/mL against Aspergillus niger [33].
Figure 6: Triazole compound 8 showing the most significant activity against Aspergillus niger and Fusarium ox...
Figure 7: Ergosterol biosynthesis inhibitor pathway.
Figure 8: Fluconazole (9).
Figure 9: Itraconazole (10).
Figure 10: Voriconazole (11).
Figure 11: Posaconazole (12).
Figure 12: Ravuconazole (13).
An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals
- Marcus Baumann,
- Ian R. Baxendale,
- Steven V. Ley and
- Nikzad Nikbin
Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57
Graphical Abstract
Figure 1: Structures of atorvastatin and other commercial statins.
Figure 2: Structure of compactin.
Scheme 1: Synthesis of pentasubstituted pyrroles.
Scheme 2: [3 + 2] Cycloaddition to prepare 5-isopropylpyrroles.
Scheme 3: Regiospecific [3 + 2] cycloaddition to prepare the pyrrole scaffold.
Scheme 4: Formation of the pyrrole core of atorvastatin via [3 + 2] cycloaddition.
Scheme 5: Formation of pyrrole 33 via the Paal–Knorr reaction.
Scheme 6: Convergent synthesis towards atorvastatin.
Figure 3: Binding pocket of sunitinib in the TRK KIT.
Scheme 7: Synthesis of sunitinib.
Scheme 8: Alternative synthesis of sunitinib.
Scheme 9: Key steps in the syntheses of sumatriptan and zolmitriptan.
Scheme 10: Introduction of the N,N-dimethylaminoethyl side chain.
Scheme 11: Japp–Klingemann reaction in the synthesis of sumatriptan.
Scheme 12: Synthesis of the intermediate sulfonyl chlorides 62 and 63.
Scheme 13: Alternative introduction of the sulfonamide.
Scheme 14: Negishi-type coupling to benzylic sulfonamides.
Scheme 15: Heck reaction used to introduce the sulfonamide side chain of naratriptan.
Scheme 16: Synthesis of the oxazolinone appendage of zolmitriptan.
Scheme 17: Grandberg indole synthesis used in the preparation of rizatriptan.
Scheme 18: Improved synthesis of rizatriptan.
Scheme 19: Larock-type synthesis of rizatriptan.
Scheme 20: Synthesis of eletriptan.
Scheme 21: Heck coupling for the indole system in eletriptan.
Scheme 22: Attempted Fischer indole synthesis of elatriptan.
Scheme 23: Successful Fischer indole synthesis for eletriptan.
Scheme 24: Mechanistic rationale for the Bischler–Möhlau reaction.
Scheme 25: Bischler-type indole synthesis used in the fluvastatin sodium synthesis.
Scheme 26: Palladium-mediated synthesis of ondansetron.
Scheme 27: Fischer indole synthesis of ondansetron.
Scheme 28: Optimised Pictet–Spengler reaction towards tadalafil.
Figure 4: Structures of carvedilol 136 and propranolol 137.
Scheme 29: Synthesis of the carbazole core of carvedilol.
Scheme 30: Alternative syntheses of 4-hydroxy-9H-carbazole.
Scheme 31: Convergent synthesis of etodolac.
Scheme 32: Alternative synthesis of etodolac.
Figure 5: Structures of imidazole-containing drugs.
Scheme 33: Synthesis of functionalised imidazoles towards losartan.
Scheme 34: Direct synthesis of the chlorinated imidazole in losartan.
Scheme 35: Synthesis of trisubstituted imidazoles.
Scheme 36: Preparation of the imidazole ring in olmesartan.
Scheme 37: Synthesis of ondansetron.
Scheme 38: Alternative route to ondansetron and its analogues.
Scheme 39: Proton pump inhibitors and synthesis of esomeprazole.
Scheme 40: Synthesis of benzimidazole core pantoprazole.
Figure 6: Structure of rabeprazole 194.
Scheme 41: Synthesis of candesartan.
Scheme 42: Alternative access to the candesartan key intermediate 216.
Scheme 43: .Medicinal chemistry route to telmisartan.
Scheme 44: Improved synthesis of telmisartan.
Scheme 45: Synthesis of zolpidem.
Scheme 46: Copper-catalysed 3-component coupling towards zolpidem.
Figure 7: Structure of celecoxib.
Scheme 47: Preparation of celecoxib.
Scheme 48: Alternative synthesis of celecoxib.
Scheme 49: Regioselective access to celecoxib.
Scheme 50: Synthesis of pazopanib.
Scheme 51: Syntheses of anastrozole, rizatriptan and letrozole.
Scheme 52: Regioselective synthesis of anastrozole.
Scheme 53: Triazine-mediated triazole formation towards anastrozole.
Scheme 54: Alternative routes to 1,2,4-triazoles.
Scheme 55: Initial synthetic route to sitagliptin.
Figure 8: Binding of sitagliptin within DPP-IV.
Scheme 56: The process route to sitagliptin key intermediate 280.
Scheme 57: Synthesis of maraviroc.
Scheme 58: Synthesis of alprazolam.
Scheme 59: The use of N-nitrosoamidine derivatives in the preparation of fused benzodiazepines.
Figure 9: Structures of itraconazole, ravuconazole and voriconazole.
Scheme 60: Synthesis of itraconazole.
Scheme 61: Synthesis of rufinamide.
Scheme 62: Representative tetrazole formation in valsartan.
Figure 10: Structure of tetrazole containing olmesartan, candesartan and irbesartan.
Scheme 63: Early stage introduction of the tetrazole in losartan.
Scheme 64: Synthesis of cilostazol.
Figure 11: Structure of cefdinir.
Scheme 65: Semi-synthesis of cefdinir.
Scheme 66: Thiazole syntheses towards ritonavir.
Scheme 67: Synthesis towards pramipexole.
Scheme 68: Alternative route to pramipexole.
Scheme 69: Synthesis of famotidine.
Scheme 70: Efficient synthesis of the hyperuricemic febuxostat.
Scheme 71: Synthesis of ziprasidone.
Figure 12: Structure of mometasone.
Scheme 72: Industrial access to 2-furoic acid present in mometasone.
Scheme 73: Synthesis of ranitidine from furfuryl alcohol.
Scheme 74: Synthesis of nitrofurantoin.
Scheme 75: Synthesis of benzofuran.
Scheme 76: Synthesis of amiodarone.
Scheme 77: Synthesis of raloxifene.
Scheme 78: Alternative access to the benzo[b]thiophene core of raloxifene.
Scheme 79: Gewald reaction in the synthesis of olanzapine.
Scheme 80: Alternative synthesis of olanzapine.
Figure 13: Access to simple thiophene-containing drugs.
Scheme 81: Synthesis of clopidogrel.
Scheme 82: Pictet–Spengler reaction in the preparation of tetrahydrothieno[3,2-c]pyridine (422).
Scheme 83: Alternative synthesis of key intermediate 422.
Figure 14: Co-crystal structures of timolol (left) and carazolol (right) in the β-adrenergic receptor.
Scheme 84: Synthesis of timolol.
Scheme 85: Synthesis of tizanidine 440.
Scheme 86: Synthesis of leflunomide.
Scheme 87: Synthesis of sulfamethoxazole.
Scheme 88: Synthesis of risperidone.
Figure 15: Relative abundance of selected transformations.
Figure 16: The abundance of heterocycles within top 200 drugs (5-membered rings).
Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers
- Daniel Crespy and
- Katharina Landfester
Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130
- require very high polymerization temperatures. Star copolymers of polyethylene glycol and polypropylene glycol were crosslinked in inverse miniemulsion via an esterification reaction with a dithiodicarboxylic acid to yield nanogels [124]. The disulfide bonds were subsequently cleaved by reduction to yield
Graphical Abstract
Figure 1: Copolymerization of 2 monomers A and B with different polarities in direct miniemlusions with the d...
Figure 2: Interfacial alternating radical copolymerization between dibutyl maleate and vinyl gluconamide for ...
Figure 3: Chemical structures of the surfmers for radical polymerization in miniemulsions: a: sodium vinylben...
Scheme 1: Synthesis of the macroinitiator for ROMP in direct miniemulsion [71].
Figure 4: Monomers used in ionic miniemulsion polymerization. a: octamethylcyclotetrasiloxane [9,74], b: 1,3,5-tris...
Figure 5: Enzymatic reactions in miniemulsion droplets (reproduced with permission from [91]. Copyright (2003) Wi...
Figure 6: Chemical structure of a: polyaniline (leucoemeraldine), b: polypyrrole, c: poly(ethylene dioxythiop...
Figure 7: Transmission electron micrograph of polyurethane capsules synthesized by interfacial polyaddition i...
Figure 8: Schematics for the polycondensation reaction between hydrophobic alcohols and carboxylic acids surr...
Scheme 2: Polyimide from the reaction performed in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoro...
Figure 9: a: TEM micrograph of the cubic structures, b: proposed mechanism for the production of the nanocube...
Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation
- Vladimir N. Boiko
Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88
- not so activating for reaction with CF3SCl. For example, thiophenol [76] forms only phenyltrifluoromethyl disulfide [70]. The presence of a methyl group and halogens requires high temperatures (100–200 °C) and the presence of catalysts (HF or BF3) for reaction and yields of the corresponding
- -nitrochlorobenzene and 2,6-diiodo-4-nitroanisole involve simultaneous reduction and substitution (Scheme 25). Trifluoromethylthiocopper is obtained by reaction of CuBr with AgSCF3 [93][99], the latter is generated from silver fluoride and carbon disulfide [90][100]. To simplify the process, Remy [101][102] suggested
- exception of 4-nitrothiophenol, the reactions are independent of the type of substituents. Unlike many thiophenoxides which bear electron-withdrawing substituents (p-Cl, 2,4-Cl2, o-SO2CHF2 and even p-SO2CF3), sodium 4-nitrothiophenoxide affords 4,4′-dinitrodiphenyl disulfide under these conditions
Graphical Abstract
Figure 1: Examples of industrial fluorine-containing bio-active molecules.
Figure 2: CF3(S)- and CF3(O)-containing pharmacologically active compounds.
Figure 3: Hypotensive candidates with SRF and SO2RF groups – analogues of Losartan and Nifedipin.
Figure 4: The variety of the pharmacological activity of RFS-substituted compounds.
Figure 5: Recent examples of compounds containing RFS(O)n-groups [12-18].
Scheme 1: Fluorination of ArSCCl3 to corresponding ArSCF3 derivatives. For references see: a[38-43]; b[41,42]; c[43]; d[44]; e[38-43,45-47]; f[38-43,48,49]; g...
Scheme 2: Preparation of aryl pentafluoroethyl sulfides.
Scheme 3: Mild fluorination of the aryl SCF2Br derivatives.
Scheme 4: HF fluorinations of aryl α,α,β-trichloroisobutyl sulfide at various conditions.
Scheme 5: Monofluorination of α,α-dichloromethylene group.
Scheme 6: Electrophilic substitution of phenols with CF3SCl [69].
Scheme 7: Introduction of SCF3 groups into activated phenols [71-74].
Scheme 8: Preparation of tetrakis(SCF3)-4-methoxyphenol [72].
Scheme 9: The interactions of resorcinol and phloroglucinol derivatives with RFSCl.
Scheme 10: Reactions of anilines with CF3SCl.
Scheme 11: Trifluoromethylsulfanylation of anilines with electron-donating groups in the meta position [74].
Scheme 12: Reaction of benzene with CF3SCl/CF3SO3H [77].
Scheme 13: Reactions of trifluoromethyl sulfenyl chloride with aryl magnesium and -mercury substrates.
Scheme 14: Reactions of pyrroles with CF3SCl.
Scheme 15: Trifluoromethylsulfanylation of indole and indolizines.
Scheme 16: Reactions of N-methylpyrrole with CF3SCl [80,82].
Scheme 17: Reactions of furan, thiophene and selenophene with CF3SCl.
Scheme 18: Trifluoromethylsulfanylation of imidazole and thiazole derivatives [83].
Scheme 19: Trifluoromethylsulfanylation of pyridine requires initial hydride reduction.
Scheme 20: Introduction of additional RFS-groups into heterocyclic compounds in the presence of CF3SO3H.
Scheme 21: Introduction of additional RFS-groups into pyrroles [82,87].
Scheme 22: By-products in reactions of pyrroles with CF3SCl [82].
Scheme 23: Reaction of aromatic iodides with CuSCF3 [93,95].
Scheme 24: Reaction of aromatic iodides with RFZCu (Z = S, Se), RF = CF3, C6F5 [93,95,96].
Scheme 25: Side reactions during trifluoromethylsulfanylation of aromatic iodides with CF3SCu [98].
Scheme 26: Reactions with in situ generated CuSCF3.
Scheme 27: Perfluoroalkylthiolation of aryl iodides with bulky RFSCu [105].
Scheme 28: In situ formation and reaction of RFZCu with aryl iodides.
Figure 6: Examples of compounds obtained using in situ generated RFZCu methodology [94].
Scheme 29: Introduction of SCF3 group into aromatics via difluorocarbene.
Scheme 30: Tetrakis(dimethylamino)ethylene dication trifluoromethyl thiolate as a stable reagent for substitut...
Scheme 31: The use of CF2=S/CsF or (CF3S)2C=S/CsF for the introduction of CF3S groups into fluorinated heteroc...
Scheme 32: One-pot synthesis of ArSCF3 from ArX, CCl2=S and KF.
Scheme 33: Reaction of aromatics with CF3S− Kat+ [115].
Scheme 34: Reactions of activated aromatic chlorides with AgSCF3/KI.
Scheme 35: Comparative CuSCF3/KI and Hg(SCF3)2/KI reactions.
Scheme 36: Me3SnTeCF3 – a reagent for the introduction of the TeCF3 group.
Scheme 37: Sandmeyer reactions with CuSCF3.
Scheme 38: Reactions of perfluoroalkyl iodides with alkali and organolithium reagents.
Scheme 39: Perfluoroalkylation with preliminary breaking of the disulfide bond.
Scheme 40: Preparation of RFS-substituted anilines from dinitrodiphenyl disulfides.
Scheme 41: Photochemical trifluoromethylation of 2,4,6-trimercaptochlorobenzene [163].
Scheme 42: Putative process for the formation of B, C and D.
Scheme 43: Trifluoromethylation of 2-mercapto-4-hydroxy-6-trifluoromethylyrimidine [145].
Scheme 44: Deactivation of 2-mercapto-4-hydroxypyrimidines S-centered radicals.
Scheme 45: Perfluoroalkylation of thiolates with CF3Br under UV irradiation.
Scheme 46: Catalytic effect of methylviologen for RF• generation.
Scheme 47: SO2−• catalyzed trifluoromethylation.
Scheme 48: Electrochemical reduction of CF3Br in the presence of SO2 [199,200].
Scheme 49: Participation of SO2 in the oxidation of ArSCF3−•.
Scheme 50: Electron transfer cascade involving SO2 and MV.
Scheme 51: Four stages of the SRN1 mechanism for thiol perfluoroalkylation.
Scheme 52: A double role of MV in the catalysis of RFI reactions with aryl thiols.
Scheme 53: Photochemical reaction of pentafluoroiodobenzene with trifluoromethyl disulfide.
Scheme 54: N- Trifluoromethyl-N-nitrosobenzene sulfonamide – a source of CF3• radicals [212,213].
Scheme 55: Radical trifluoromethylation of organic disulfides with ArSO2N=NCF3.
Scheme 56: Barton’s S-perfluoroalkylation reactions [216].
Scheme 57: Decarboxylation of thiohydroxamic esters in the presence of C6F13I.
Scheme 58: Reactions of thioesters of trifluoroacetic and trifluoromethanesulfonic acids in the presence of ar...
Scheme 59: Perfluoroalkylation of polychloropyridine thiols with xenon perfluorocarboxylates or XeF2 [222,223].
Scheme 60: Interaction of Xe(OCORF)2 with nitroaryl disulfide [227].
Scheme 61: Bi(CF3)3/Cu(OCOCH3)2 trifluoromethylation of thiophenolate [230].
Scheme 62: Reaction of fluorinated carbanions with aryl sulfenyl chlorides.
Scheme 63: Reaction of methyl perfluoromethacrylate with PhSCl in the presence of fluoride.
Scheme 64: Reactions of ArSCN with potassium and magnesium perfluorocarbanions [237].
Scheme 65: Reactions of RFI with TDAE and organic disulfides [239,240].
Scheme 66: Decarboxylation of perfluorocarboxylates in the presence of disulfides [245].
Scheme 67: Organization of a stable form of “CF3−” anion in the DMF.
Scheme 68: Silylated amines in the presence of fluoride can deprotonate fluoroform for reaction with disulfide...
Figure 7: Other examples of aminomethanols [264].
Scheme 69: Trifluoromethylation of diphenyl disulfide with PhSO2CF3/t-BuOK.
Scheme 70: Amides of trifluoromethane sulfinic acid are sources of CF3− anion.
Scheme 71: Trifluoromethylation of various thiols using “hyper-valent” iodine (III) reagent [279].
Scheme 72: Trifluoromethylation of p-nitrothiophenolate with diaryl CF3 sulfonium salts [280].
Scheme 73: Trifluoromethyl transfer from dibenzo (CF3)S-, (CF3)Se- and (CF3)Te-phenium salts to thiolates [283].
Scheme 74: Multi-stage paths for synthesis of dibenzo-CF3-thiophenium salts [61].
Bis(oxazolines) based on glycopyranosides – steric, configurational and conformational influences on stereoselectivity
- Tobias Minuth and
- Mike M. K. Boysen
Beilstein J. Org. Chem. 2010, 6, No. 23, doi:10.3762/bjoc.6.23
- phthalimido protected precursor 7 (Scheme 3). Introduction of the 3-xanthogenate with carbon disulfide and methyl iodide yielded 17, which was cleanly deoxygenated in high yield by tributyltin hydride under standard conditions [32][33]. From the resulting compound 18, the ligands 3-deoxy glucoBox 21 with
Graphical Abstract
Scheme 1: New glucosamine-based bis(oxazoline) ligands with their pyranose conformation and application in as...
Figure 1: Planned modifications at pyranose position 3 of carbohydrate bis(oxazolines).
Scheme 2: Synthesis of allo-configured bis(oxazolines) 3-O-Ac alloBox (14) and Ac alloBox (16) from thiogluco...
Scheme 3: Preparation of ligands 3-deoxy glucoBox (21) and Ac 3-deoxy glucoBox (23) from key intermediate 7.
Scheme 4: Preparation of ligand 3-O-Formyl glucoBox (26) from bis(amide) 24.
Figure 2: Impact of structural ligand modifications on the stereoselectivity of cyclopropanations.
Convergent syntheses of LeX analogues
- An Wang,
- Jenifer Hendel and
- France-Isabelle Auzanneau
Beilstein J. Org. Chem. 2010, 6, No. 17, doi:10.3762/bjoc.6.17
- respectively to the n-hexyl and 6-aminohexyl trisaccharide targets. Unexpectedly, the 6-acetylthiohexyl analogue underwent desulfurization and gave the n-hexyl glycoside product, whereas the 6-benzylthiohexyl analogue gave the desired disulfide trisaccharide dimer. This study constitutes a particularly
- conditions did not lead to the desired corresponding thiol or disulfide product but produced the hexyl glycoside 1. The mechanism proposed to explain this reductive desulfurization is shown in Scheme 4. It involves first a single electron transfer to the thioacetyl group that is followed by the cleavage of
- -benzylthiohexyl glycoside 32 under Birch reduction conditions did not lead to desulfurization and gave the disulfide trisaccharide dimer 3. Under these reductive conditions, and based on the work by Seeberger et al. [52], we did not expect the formation of the disulfide dimer as the major product but rather that
Graphical Abstract
Figure 1: Structure of Lex analogues 1–3.
Figure 2: Monosaccharide glycosyl acceptors (4–6) and donors (7–9) used in this study.
Scheme 1: Synthesis of monosaccharide glycosyl acceptors 4–6.
Scheme 2: Synthesis of the galactosyl donor 8.
Scheme 3: Convergent synthesis of trisaccharides 29–32.
Scheme 4: Proposed mechanism for the desulfurization of thioacetate 31 under dissolving metal conditions.
A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis
- Magnus Rueping and
- Boris J. Nachtsheim
Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6
- developed [122]. A first catalytic enantioselective Friedel–Crafts alkylation with propargyl alcohols as electrophile has been developed by Nishibayashi and co-workers. Chirality was introduced by a thiolate-bridged diruthenium complex which is based on optically active disulfide ligand 120. 2-Alkylfurans
Graphical Abstract
Scheme 1: AlCl3-mediated reaction between amyl chloride and benzene as developed by Friedel and Crafts.
Figure 1: Most often used metal salts for catalytic FC alkylations and hydroarylations of arenes.
Figure 2: 1,1-diarylalkanes with biological activity.
Scheme 2: Alkylating reagents and side products produced.
Scheme 3: Initially reported TeCl4-mediated FC alkylation of 1-penylethanol with toluene.
Scheme 4: Sc(OTf)3-catalyzed FC benzylation of arenes.
Scheme 5: Reductive FC alkylation of arenes with arenecarbaldehydes.
Scheme 6: Iron(III)-catalyzed FC benzylation of arenes and heteroarenes.
Scheme 7: A gold(III)-catalyzed route to beclobrate.
Scheme 8: Catalytic FC-type alkylations of 1,3-dicarbonyl compounds.
Scheme 9: Iron(III)-catalyzed synthesis of phenprocoumon.
Scheme 10: Bi(OTf)3-catalyzed FC alkylation of benzyl alcohols developed by Rueping et al.
Scheme 11: (A) Bi(OTf)3-catalyzed intramolecular FC alkylation as an efficient route to substituted fulvenes. ...
Scheme 12: FC-type glycosylation of 1,2-dimethylindole and trimethoxybenzene.
Scheme 13: FC alkylation with highly reactive ferrocenyl- and benzyl alcohols. The reaction proceeds even with...
Scheme 14: Reductive FC alkylation of arenes with benzaldehyde and acetophenone catalyzed by the Ir-carbene co...
Scheme 15: Formal synthesis of 1,1-diarylalkanes from benzyl alcohols and styrenes.
Scheme 16: (A) Mo-catalyzed hydroarylation of styrenes and cyclohexenes. (B) Hydroalkylation–cyclization casca...
Scheme 17: Bi(III)-catalyzed hydroarylation of styrenes with arenes and heteroarenes.
Scheme 18: BiCl3-catalyzed ene/FC alkylation reaction cascade – A fast access to highly arylated dihydroindene...
Scheme 19: Au(I)/Ag(I)-catalyzed hydroarylation of indoles with styrenes, aliphatic and cyclic alkenes.
Scheme 20: First transition-metal-catalyzed ortho-hydroarylation developed by Beller et al.
Scheme 21: (A) Ti(IV)-mediated rearrangement of an N-benzylated aniline to the corresponding ortho-alkylated a...
Scheme 22: Dibenzylation of aniline gives potentially useful amine-based ligands in a one-step procedure.
Scheme 23: FC-type alkylations with allyl alcohols as alkylating reagents – linear vs. branched product format...
Scheme 24: (A) First catalytic FC allylation and cinnamylation using allyl alcohols and its derivatives. (B) E...
Scheme 25: FC allylation/cyclization reaction yielding substituted chromanes.
Scheme 26: Synthesis of (all-rac)-α-tocopherol utilizing Lewis- and strong Brønsted-acids.
Scheme 27: Au(III)-catalyzed cinnamylation of arenes.
Scheme 28: “Exhaustive” allylation of benzene-1,3,5-triol.
Scheme 29: Palladium-catalyzed allylation of indole.
Scheme 30: Pd-catalyzed synthesis of pyrroloindoles from L-tryptophane.
Scheme 31: Ru(IV)-catalyzed allylation of indole and pyrroles with unique regioselectivity.
Scheme 32: Silver(I)-catalyzed intramolecular FC-type allylation of arenes and heteroarenes.
Scheme 33: FC-type alkylations of arenes using propargyl alcohols.
Scheme 34: (A) Propargylation of arenes with stoichiometric amounts of the Ru-allenylidene complex 86. (B) Fir...
Scheme 35: Diruthenium-catalyzed formation of chromenes and 1H-naphtho[2,1-b]pyrans.
Scheme 36: Rhenium(V)-catalyzed FC propargylations as a first step in the total synthesis of podophyllotoxin, ...
Scheme 37: Scandium-catalyzed arylation of 3-sulfanyl- and 3-selanylpropargyl alcohols.
Scheme 38: Synthesis of 1,3-diarylpropynes via direct coupling of propargyl trichloracetimidates and arenes.
Scheme 39: Diastereoselective substitutions of benzyl alcohols.
Scheme 40: (A) First diastereoselective FC alkylations developed by Bach et al. (B) anti-Selective FC alkylati...
Scheme 41: Diastereoselective AuCl3-catalyzed FC alkylation.
Scheme 42: Bi(OTf)3-catalyzed alkylation of α-chiral benzyl acetates with silyl enol ethers.
Scheme 43: Bi(OTf)3-catalyzed diastereoselective substitution of propargyl acetates.
Scheme 44: Nucelophilic substitution of enantioenriched ferrocenyl alcohols.
Scheme 45: First catalytic enantioselective propargylation of arenes.
Part 2. Mechanistic aspects of the reduction of S-alkyl- thionocarbonates in the presence of triethylborane and air
- Florent Allais,
- Jean Boivin and
- Van Tai Nguyen
Beilstein J. Org. Chem. 2007, 3, No. 46, doi:10.1186/1860-5397-3-46
- possible source of hydrogen atom. This by-product is produced by reaction of ethyl radical, generated from Et3B, with the xanthate function. Deuterated compounds 3–5 were easily prepared from ethanol, carbon disulfide and ethyl bromide (Figure 2). The results reported in Table 2 clearly show that no
Graphical Abstract
Figure 1: Xanthates 1a, 2a and their corresponding alkanes.
Figure 2: Deuterated O-ethyl-S-ethyl dithiocarbonates 3–5, deuterated adduct 1d and alkane 1e.
Figure 3: Kinetics of the reduction of compound 1a in C6H6 at 20°C.
Scheme 1: Preparation of Et3B-d15.
The use of chiral lithium amides in the desymmetrisation of N-trialkylsilyl dimethyl sulfoximines
- Matthew J. McGrath and
- Carsten Bolm
Beilstein J. Org. Chem. 2007, 3, No. 33, doi:10.1186/1860-5397-3-33
- , Entry 1), affording 2c in high yield and improved ee (86% yield, 70% ee, Table 2, Entry 2). When N-(diphenylmethylene)-toluenesulfonamide was used as electrophile the sulfoximine adduct 2d was obtained in low yield and ee (Table 2, Entry 3). In contrast, diphenyl disulfide gave sulfide 2e in accepee but
Graphical Abstract
Scheme 1: Desymmetrisation of N-trialkylsilyldimethylsulfoximines using chiral bases
Scheme 2: Preparation of N-trialkylsilyl dimethyl sulfoximine derivatives
Figure 1: The diamine (-)-sparteine and three chiral lithium amide bases.
Scheme 3: Preparation of vinyl sulfoximines
Figure 2: Selected NMR Characteristics of sulfoximine amides 12, 13 and 14.
Scheme 4: Preparation of O-methyl mandelamide derivatives (S,R)-12 and (R,R)-12
Scheme 5: The influence of (S,S)-bis(1-phenylethyl)amine on the ee of 1b
Aroylketene dithioacetal chemistry: facile synthesis of 4-aroyl- 3-methylsulfanyl- 2-tosylpyrroles from aroylketene dithioacetals and TosMIC
- H. Surya Prakash Rao and
- S. Sivakumar
Beilstein J. Org. Chem. 2007, 3, No. 31, doi:10.1186/1860-5397-3-31
- disulfide and sodium tert-butoxide followed by alkylation with dimethyl sulfate. The reaction of TosMIC 2 with AKDTA 6 provided the trisubstituted pyrrole 7 in excellent yield. As anticipated, the 1H NMR spectrum of pyrenoylpyrrole 7 exhibited a doublet for C2'-H of pyrene unit as a doublet at δ 8.37 ppm
Graphical Abstract
Scheme 1: Cycloaddition of TosMIC to AKDTAs provide 2,3,4-trisubstituted pyrroles 3 and imidazole 4.
Scheme 2: Base induced dimerization of TosMIC to furnish imidazole 4.
Figure 1: Structure of 2,3,4-trisubstituted pyrroles 3a-g synthesized in this study.
Scheme 3: Synthesis of AKDTA 6 and it's further transformation to pyrrole 7.
Scheme 4: Regio-selectivity in the reaction of TosMIC with 8.
Scheme 5: Competition experiments involving one mmol each of TosMIC with AKDTA 1a and phenyl vinyl ketone 10 ...
