Selective C–S Bond Constructions Using Inorganic Sulfurs via Photoinduced Electron Donor–Acceptor Activation

Abstract

By complementing traditional transition metal catalysis, photoinduced catalysis has emerged as a versatile and sustainable way to achieve carbon−heteroatom bond formation. This work discloses a visible-light-induced reaction for the formation of a C−S bond from aryl halides and inorganic sulfuration agents via electron donor−acceptor (EDA) complex photocatalysis. Divergent formations of organic sulfide and disulfide have been demonstrated under mild conditions. Preliminary mechanistic studies suggest that visible-light-induced intracomplex charge transfer within the monosulfide-anion-containing EDA complex permits the C−S bond construction reactivity.

Photocatalyst‐ and Transition‐Metal‐Free Light‐Induced Formation of Carbon‐Chalcogen Bonds

“…Similarly, the Chen group reported another photochemical selective C−S bond formation employing (hetero)aryl halides through the EDA complex [61] . A range of disulfides were synthesized utilizing inorganic K 2 S as the sulfur source in the absence of any photocatalyst.…”

“…Similarly, the Chen group reported another photochemical selective CÀ S bond formation employing (hetero)aryl halides through the EDA complex. [61] A range of disulfides were synthesized utilizing inorganic K 2 S as the sulfur source in the absence of any photocatalyst. Following this work, a dehalogenative intramolecular CÀ S bond formation using orthohalothiobenzanilides under photoinduced catalyst-free conditions was developed by Li and co-workers.…”

Transition Metal and Photocatalyst Free Arylation via Photoexcitable Electron Donor Acceptor Complexes:Mediation and Catalysis

“…proposed a novel access point to diaryl disulfides 25 through the interaction between aryl halides and potassium sulfide (Scheme 15). [20] By use of this protocol several electron‐deficient diaryl disulfides have been prepared in batch and in flow conditions, including those bearing an unprotected carbonyl group. The mechanism for this reaction is in line with the classical EDA‐based arylation (Scheme 1, A), where the interaction between the aryl halide and potassium sulfide results in the formation of the aryl thiolate, which is further oxidized to the corresponding disulfide through another EDA‐mediated interaction with 1 .…”

Visible Light Induced Photocatalyst‐Free C−X (X=B, C, O, P,S, Se) Bond Formation of Aryl Halides

“…In 2022, synthesis of disulfides 20 from aryl halides (I, Br) 8 utilizing K 2 S as a sulfuration agent under visible light illumination was accomplished by Chen and co‐workers (Scheme 10). [18b] Unfortunately, the strategy was limited to electron‐deficient aryl halides. The UV‐vis spectroscopy implies the formation of an EDA‐complex ( EDA‐I ) between monosulfide anion and aryl halide 8 , which upon photoexcitation inducing a SET to produce the aryl radical 10A and monosulfide radical anion 10B .…”