Photocatalytic Silylation of Aryl Alkynoates: Synthesis of Silylated Coumarins

Abstract

Herein, we reported the photocatalytic synthesis of 3‐silyl coumarins using hydrosilanes as the silyl radical source with aryl alkynoates. Readily prepared N‐aminopyridinium salts act as hydrogen atom transfer reagents for generating silyl radicals under photoredox catalysis. The reaction proceeds through silyl radical addition to alkyne followed by radical cascade cyclization/migration with subsequent oxidation and aromatization to give desired 3‐silyl coumarins in 34% to 89% yield.