Photocatalytic formation of carbon-sulfur bonds

Abstract

This review summarizes recent developments in photocatalyzed carbon-sulfur bond formation. General concepts, synthetic strategies and the substrate scope of reactions yielding thiols, disulfides, sulfoxides, sulfones and other organosulfur compounds are discussed together with the proposed mechanistic pathways.

Keywords: disulfides; photocatalysis; sulfones; sulfoxides; thiols; visible light.

Scheme 1

General overview over the sulfur-based substrates and reactive intermediates that are discussed in this review.

Scheme 2

Photoredox-catalyzed radical thiol–ene reaction, applying [Ru(bpz)₃](PF₆)₂ as photocatalyst.

Scheme 3

Photoredox-catalyzed thiol–ene reaction of aliphatic thiols with alkenes enabled by aniline derivatives as redox mediators.

Scheme 4

Photoredox-catalyzed radical thiol–ene reaction for the postfunctionalization of polymers (a) and natural lignin (b).

Scheme 5

Photoredox-catalyzed thiol–ene reaction enabled by bromotrichloromethane as redox additive.

Scheme 6

Photoredox-catalyzed preparation of β-ketosulfoxides with Eosin Y as organic dye as photoredox catalyst.

Scheme 7

Greaney’s photocatalytic radical thiol–ene reaction, applying TiO₂ nanoparticles as photocatalyst.

Scheme 8

Fadeyi’s photocatalytic radical thiol–ene reaction, applying Bi₂O₃ as photocatalyst.

Scheme 9

Ananikov’s photocatalytic radical thiol-yne reaction, applying Eosin Y as photocatalyst.

Scheme 10

Organocatalytic visible-light photoinitiated thiol–ene coupling, applying phenylglyoxylic acid as organophotocatalyst.

Scheme 11

Xia’s photoredox-catalyzed synthesis of 2,3-disubstituted benzothiophenes, applying 9-mesityl-10-methylacridinium perchlorate as organic photocatalyst.

Scheme 12

Wang’s metal-free photoredox-catalyzed radical thiol–ene reaction, applying 9-mesityl-10-methylacridinium tetrafluoroborate as organic photocatalyst.

Scheme 13

Visible-light benzophenone-catalyzed metal- and oxidant-free radical thiol–ene reaction.

Scheme 14

Visible-light catalyzed C-3 sulfenylation of indole derivatives using Rose Bengal as organic dye.

Scheme 15

Photocatalyzed radical thiol–ene reaction and subsequent aerobic sulfide-oxidation with Rose Bengal or Eosin Y as organic photocatalysts.

Scheme 16

Photoredox-catalyzed synthesis of diaryl sulfides.

Scheme 17

Photocatalytic cross-coupling of aryl thiols with aryl diazonium salts, using Eosin Y as photoredox catalyst.

Scheme 18

Photocatalyzed cross-coupling of aryl diazonium salts with cysteines in batch and in a microphotoreactor.

Scheme 19

Fu’s [Ir]-catalyzed photoredox arylation of aryl thiols with aryl halides.

Scheme 20

Fu’s photoredox-catalyzed difluoromethylation of aryl thiols.

Scheme 21

C–S cross-coupling of thiols with aryl iodides via [Ir]-photoredox and [Ni]-dual-catalysis.

Scheme 22

C–S cross-coupling of thiols with aryl bromides, applying 3,7-bis-(biphenyl-4-yl)-10-(1-naphthyl)phenoxazine as organic photocatalyst in combination with transition metal catalysis.

Scheme 23

Collin’s photochemical dual-catalytic cross-coupling of thiols with bromoalkynes.

Scheme 24

Visible-light-promoted C–S cross-coupling via intermolecular electron donor–acceptor complex formation.

Scheme 25

Li’s visible-light photoredox-catalyzed thiocyanation of indole derivatives with Rose Bengal as photocatalyst.

Scheme 26

Hajra’s visible-light photoredox-catalyzed thiocyanation of imidazoheterocycles with Eosin Y as photocatalyst.

Scheme 27

Wang’s photoredox-catalyzed thiocyanation reaction of indoles, applying heterogeneous TiO₂/MoS₂ nanocomposite as photocatalyst.

Scheme 28

Yadav’s photoredox-catalyzed α-C(sp³)–H thiocyanation reaction for tertiary amines, applying Eosin Y as photocatalyst.

Scheme 29

Yadav’s photoredox-catalyzed synthesis of 5-aryl-2-imino-1,3-oxathiolanes.

Scheme 30

Yadav’s photoredox-catalyzed synthesis of 1,3-oxathiolane-2-thiones.

Scheme 31

Li’s photoredox catalysis for the preparation of 2-substituted benzothiazoles, applying [Ru(bpy)₃](PF₆)₂ as photocatalyst.

Scheme 32

Lei’s external oxidant-free synthesis of 2-substituted benzothiazoles by merging photoredox and transition metal catalysis.

Scheme 33

Metal-free photocatalyzed synthesis of 2-aminobenzothiazoles, applying Eosin Y as photocatalyst.

Scheme 34

Metal-free photocatalyzed synthesis of 1,3,4-thiadiazoles, using Eosin Y as photocatalyst.

Scheme 35

Visible-light photoredox-catalyzed preparation of benzothiophenes with Eosin Y.

Scheme 36

Visible-light-induced KOH/DMSO superbase-promoted preparation of benzothiophenes.

Scheme 37

Jacobi von Wangelin’s photocatalytic approach for the synthesis of aryl sulfides, applying Eosin Y as photocatalyst.

Scheme 38

Visible-light photosensitized α-C(sp³)–H thiolation of aliphatic ethers.

Scheme 39

Visible-light photocatalyzed cross-coupling of alkyl and aryl thiosulfates with aryl diazonium salts, applying [Ru(bpy)₃]Cl₂.

Scheme 40

Visible-light photocatalyzed, controllable sulfenylation and sulfoxidation with organic thiosulfate salts.

Scheme 41

Rastogi’s photoredox-catalyzed methylsulfoxidation of aryl diazonium salts, using [Ru(bpy)₃]Cl₂ as photocatalyst.

Scheme 42

a) Visible-light metal-free Eosin Y-catalyzed procedure for the preparation of vinyl sulfones from alkyl and (hetero)aryl sulfinate salts. b) Visible-light catalyzed preparation of vinyl sulfones, applying heterogeneous carbon nitride photocatalysts.

Scheme 43

Visible-light photocatalyzed cross-coupling of sodium sulfinates with secondary enamides.

Scheme 44

Wang’s photocatalyzed oxidative cyclization of phenyl propiolates with sulfinic acids, applying Eosin Y as organic dye.

Scheme 45

Lei’s sacrificial oxidant-free synthesis of allyl sulfones by merging photoredox and transition metal catalysis.

Scheme 46

Photocatalyzed Markovnikov-selective radical/radical cross-coupling of aryl sulfinic acids and terminal alkynes.

Scheme 47

Visible-light Eosin Y induced cross-coupling of aryl sulfinic acids and styrene derivatives, affording β-ketosulfones.

Scheme 48

Photoredox-catalyzed bicyclization of 1,7-enynes with sulfinic acids, applying Eosin Y as photocatalyst.

Scheme 49

Visible-light-accelerated C–H-sulfinylation of arenes and heteroarenes.

Scheme 50

Visible-light photoredox-catalyzed β-selenosulfonylation of electron-rich olefins, applying [Ru(bpy)₃]Cl₂ as photocatalyst.

Scheme 51

Photocatalyzed preparation of β-chlorosulfones from the respective olefins and p-toluenesulfonyl chloride, using [Ru(bpy)₃]Cl₂ as photocatalyst.

Scheme 52

a) Photocatalyzed preparation of β-amidovinyl sulfones from sulfonyl chlorides. b) Preparation of β-ketosulfones by photoredox-catalyzed coupling of sulfonyl chlorides with enol acetates.

Scheme 53

Visible-light photocatalyzed sulfonylation of aliphatic tertiary amines, applying [Ru(bpy)₃](PF₆)₂ as photocatalyst.

Scheme 54

Reiser’s visible-light photoredox-catalyzed preparation of β-hydroxysulfones from sulfonyl chlorides and alkenes.

Scheme 55

a) Sun’s visible-light-catalyzed approach for the preparation of isoquinolinonediones, applying [fac-Ir(ppy)₃]. b) Xia’s procedure, applying [Ru(bpy)₃]Cl₂ or [Ir(ppy)₂dtbbpy]PF₆ as photoredox catalysts.

Scheme 56

Visible-light photocatalyzed sulfonylation/cyclization of vinyl azides, applying [Ru(bpy)₃]Cl₂ as photocatalyst.

Scheme 57

Visible-light photocatalyzed procedure for the formation of β-ketosulfones from aryl sulfonyl chlorides and alkenes.

Scheme 58

Zheng’s method for the sulfenylation of indole derivatives, applying sulfonyl chlorides via visible-light photoredox catalysis.

Scheme 59

Cai’s visible-light induced synthesis of β-ketosulfones from sulfonyl hydrazines and alkynes.

Scheme 60

Photoredox-catalyzed approach for the preparation of vinyl sulfones from sulfonyl hydrazines and cinnamic acids.

Scheme 61

Jacobi von Wangelin’s visible-light photocatalyzed chlorosulfonylation of anilines.

Scheme 62

Three-component photoredox-catalyzed synthesis of N-amino sulfonamides, applying PDI as organic dye.

Scheme 63

Visible-light induced preparation of complex sulfones from oximes, silyl enol ethers and SO₂.