Anti-Markovnikov hydrosulfenylation of unactivated alkenes/alkynes via visible-light organic photocatalysis

Abstract

Photocatalytic difunctionalization of alkenes/alkynes offers one of the most efficient methods to access structurally diverse molecules from readily available precursors with excellent atom- and step-economic attributes. However, reactions involving unactivated alkenes/alkynes have been proven to be elusive and remain underdeveloped. Here, we report a Rose Bengal (RB)-catalyzed hydrosulfenylation of unactivated alkenes/alkynes using thiols as abundant starting materials and citric acid as a biomass-derived acid additive. Mechanistic studies revealed that the transformation proceeds via thiol–ene/yne click reactions, followed by reactive oxygen species and in situ-generated peroxide-mediated oxidation processes. This protocol exhibits good functional group compatibility with excellent regioselectivity, affording a diverse range of aryl alkyl, dialkyl, and vinyl sulfoxides as valuable synthetic building blocks in organic synthesis.