A general route to fluorinated 3,3-disubstituted 2-oxindoles via a photoinduced radical cyclization of N-arylacrylamides under catalyst-free conditions

Abstract

A catalyst-free radical cyclization of N-arylacrylamides with fluorinated alkyl iodides or the Togni reagent enabled by photoenergy is presented for the first time. Under ultraviolet irradiation, the generation of fluorinated 3,3-disubstituted 2-oxindoles proceeds smoothly without any metals or photoredox catalysts. The broad reaction scope is demonstrated with good functional group tolerance. During the process, fluorinated alkyl groups can be easily incorporated.