Visible-Light-Enabled Three-Component Carboamidation of Alkenes with Aryl Thianthrenium Salts

Abstract

Herein, we report a visible-light-enabled strategy for activating aryl thianthrenium salts that enables a three-component Ritter-type carboamidation of alkenes with nitriles/H2O. Under neutral and mild irradiation, C-C and C-N bonds are sequentially formed in a single operation to deliver diverse benzylamides with broad functional-group tolerance. A wide range of aryl thianthrenium salts as well as diverse styrenes are compatible, and late-stage diversification of pharmaceutically relevant motifs is readily achieved. Mechanistic studies suggest that a single-electron transfer (SET) pathway is likely operative, involving reductive quenching of the excited Ir(III) photocatalyst by thianthrene, followed by reduction of the arylthianthrenium salt by the resulting Ir(II) species to generate an aryl radical. This work expands the synthetic utility of aryl thianthrenium salts and provides a modular entry to architecturally complex benzylamides from simple alkene feedstocks.