Development of Photoredox-Assisted Direct α-Alkylation Reactions of Ketones with Arylalkenes Using a Catalytic Amount of LiOtBu as a Brønsted Base

Abstract

Photoinduced direct α-alkylation reactions of ketones with arylalkenes using an organophotocatalyst and a Brønsted base were developed. It was found that the choice of both Brønsted base and photocatalyst was crucial, and in the presence of catalytic amounts of 2,4,6-tris(diphenylamino)-3,5-difluorobenzonitrile (3DPA2FBN) and LiO^tBu, the desired reactions of ketones with styrene analogues proceeded smoothly under blue-LED light irradiation to afford the products in moderate to high yields. This method constitutes an atom-economical alkylation process for α-functionalization of both cyclic and acyclic ketones.