Unlocking the Potential of & beta;-Fragmentation of Aminophosphoranyl Radicals for Sulfonyl Radical Reactions

Abstract

Exploiting & beta;-scission in aminophosphoranyl radicalsfor radical-mediatedtransformations has been a longstanding challenge. In this study,we investigated the untapped potential of & beta;-fragmentation inaminophosphoranyl radicals by leveraging the unique properties ofthe P-N bond and the substituents of P(III) reagents. Our approachcarefully considers factors such as cone angle and electronic propertiesof phosphine and employs density functional theory (DFT) calculationsto probe structural and molecular orbital influence. We successfullyinduced & beta;-fragmentation through N-S bond cleavage ofaminophosphoranyl radicals under visible light and mild conditions,generating a range of sulfonyl radicals derived from pyridinium saltsvia the photochemical activity of electron donor-acceptor (EDA)complexes. This innovative synthetic strategy exhibits broad applicability,including late-stage functionalization, and paves the way for valuablesulfonyl radical-mediated reactions, such as alkene hydrosulfonylation,difunctionalization, and pyridylic C-H sulfonylation.