Formal β-C−H Arylation of Aldehydes and Ketones by Cooperative Nickel and Photoredox Catalysis

Abstract

α-C−H-functionalization of ketones and aldehydes has been intensively explored in organic synthesis. The functionalization of unactivated β-C−H bonds in such carbonyl compounds is less well investigated and developing a general method for their β-C−H arylation remains challenging. Herein we report a method that uses cooperative nickel and photoredox catalysis for the formal β-C−H arylation of aldehydes and ketones with (hetero)aryl bromides. The method features mild conditions, remarkable scope and wide functional group tolerance. Importantly, the introduced synthetic strategy also allows the β-alkenylation, β-alkynylation and β-acylation of aldehydes under similar conditions. Mechanistic studies revealed that this transformation proceeds through a single electron oxidation/Ni-mediated coupling/reductive elimination cascade.