Visible-light induced oxidant-free oxidative cross-coupling for constructing allylic sulfones from olefins and sulfinic acids

Abstract

An oxidant-free dehydrogenative sulfonylation of α-methyl-styrene derivatives was developed for the construction of allylic sulfones by using eosin Y as a photosensitizer in conjunction with a cobaloxime catalyst. The process features a low-cost metal catalyst and atom economy, which provides an appealing strategy for future synthetic chemistry.

Water-promoted C-S bond formation reactions

“…Therefore, tremendous effort has been directed towards the development of efficient methods to access this class of compounds. Reported methods included the use of transition-metal catalyzed (oxidative)-cross-coupling 9 reactions, Tsuji–Trost reaction 10 , and hydrosulfination 11 by using the highly reactive allylic substrates and sulfinyl nucleophiles. Coupled with environmental and economy concerns, the development of energy-efficient and greener synthetic methods from nontoxic, inexpensive, readily available and environmentally benign feedstock is extremely attractive and essential.…”

Photoredox-catalyzed branch-selective pyridylation of alkenes for the expedient synthesis of Triprolidine

“…Design plan. We hypothesized that sodium sulfinates would be the ideal reusable radical precursors, due to the unique properties of which: (i) sufinates have been recently employed as efficient sulfonyl coupling partners in photoredox catalysis [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] ; (ii) it is well known that the alkyl sulfones would be prone to undergo desulfonylation under basic conditions [63][64][65] . As depicted in Fig.…”

Metal‐Free Visible‐Light Photocatalytic Tandem Radical Addition–Cyclization Strategy for the Synthesis of Sulfonyl‐Containing Isoquinolinediones

“…On the basis of above mechanistic studies and related literature, we proposed a plausible process for the current photocatalytic radical addition/cyclization reaction (Scheme ). First, the excited state of photocatalyst, eosin Y*, which is formed reversibly upon visible light irradiation, is reductively quenched by the sulfinate 2a (E 1/2 = 0.47 V vs. SCE, see SI, Figure S5) to afford [eosin Y] · – (E 1/2 red [eosin Y*/eosin Y · – ] = +0.83 V vs. SCE) and sulfonate radical A .…”

“…Next, radical B undergoes a radical addition to alkene 1a generating new radical C , which can be intramolecularly cyclized to form intermediate D . Product 3a and eosin Y‐H hydride[20b] are then given from intermediate D and eosin Y radical anion by single electron transfer (SET) and proton transfer (PT). Finally, the eosin Y‐H hydride reacts with proton to release H 2 and regenerate eosin Y to complete the photocatalytic cycle.…”