Iridium‐Catalyzed Asymmetric Allylic Benzylation with Photogenerated Hydroxy‐o‐Quinodimethanes

Abstract

An iridium‐catalyzed asymmetric allylic benzylation of aryl vinyl carbinols under light irradiation is described. 2‐Methylbenzophenone derivatives are employed and activated to hydroxy‐o‐quinodimethanes by an ultraviolet (UV) light. This approach enables asymmetric allylic benzylation with high enantioselectivity (up to 99 % ee) from readily available 2‐methylbenzophenones without the utilization of strong bases, and pre‐activation or pre‐functionalization of the substrates. Moreover, deuterium experiments reveal the generation of nucleophilic benzyl species from 2‐methylbenzophenone under UV irradiation.