Visible-Light-Promoted Radical gem-Selenosulfonylation or -Iodosulfonylation of 2,2,2-Trifluorodiazoethane under Photosensitizer-Free Conditions

A visible-light-promoted radical gem-difunctionalization of trifluorodiazoethane with RSO₂X (X = SeR', I) for the synthesis of α-seleno or α-iodo trifluoroethyl sulfones is described. This atom-economical reaction is external-photocatalyst- and additive-free and uses nontoxic ethyl acetate as the solvent. The resultant products, which incorporate sulfonyl, trifluoromethyl, and iodo or selenyl functional groups onto one carbon atom, can serve as versatile building blocks. A major synthetic application was demonstrated by ATRA reactions with various terminal alkynes.