Skeletal Editing of Benzodithiol‐3‐ones via S‐to‐C Atom Swap

Comprehensive Summary An expedient organophosphine‐mediated skeletal editing of benzodithiol‐3‐ones is demonstrated herein, which represents the first example for metal‐free transformations of benzodithiol‐3‐ones via S‐to‐C atom swap. This unprecedented formal [4+1] cycloadditions of benzodithiol‐3‐ones and α‐halocarbonyls enable divergent synthesis of diverse 3‐hydroxybenzo[ b ]thiophenes and benzo[ b ]thiophen‐3(2 H )‐ones, the products of which were determined by the substitution pattern of the α‐halocarbonyls. The newly‐developed S‐to‐C exchange strategy allows for the streamline assembly of valuable sulfur‐heterocycles via sulfur‐deletion and carbon‐insertion. This method is distinguished by its transition‐metal‐free nature, elimination of inert gas protection requirements, convenient operation, mild conditions, extensive substrate generality and decent yields. Of note, the current protocol could be readily applied to late‐stage diversification of structurally varied bioactive molecules, underscoring the potential applicability and practical utility of this metal‐free skeletal editing strategy.