Single electron transfer/hydrogen atom transfer synergistic catalysis for green synthesis of benzyl thioesters†

Benzyl thioesters, a specific subclass of thioesters, are widely used as important intermediates in organic synthesis and the pharmaceutical field. Traditional synthetic methods for benzyl thioesters often suffer from toxic sulfur sources, harsh conditions, complex procedures, or low yields, posing inherent safety and sustainability challenges. Herein, we describe a novel synergistic photocatalytic system that integrates single electron transfer (SET) of a metal-chalcogenide-cluster-based catalyst and hydrogen atom transfer (HAT) of a polyoxometalate-based catalyst, achieving the green synthesis of benzyl thioesters from readily available feedstocks: elemental sulfur, benzyl chlorides, and aldehydes. This protocol operates via an optional dual sulfur radical-based coupling pathway and exhibits a remarkably broad substrate scope, i.e. compatible with a wide variety of benzyl chlorides and aldehydes, enabling atom-, step-, and redox-economical synthesis. Furthermore, the system demonstrates the late-stage functionalization of various complex natural products and the synthesis of target bioactive molecules, such as a potential hydrogen sulfide donor and a snake venom antagonist. Our work offers a green photocatalytic method for the synthesis of benzyl thioesters and opens new avenues for the construction of diverse C–S bonds in organic and pharmaceutical syntheses.