Enantioselective C2-Allylation of Benzimidazoles Using 1,3-Diene Pronucleophiles
journal contributionposted on 01.03.2021, 20:34 authored by James Levi Knippel, Yuxuan Ye, Stephen L. Buchwald
Although substituted benzimidazoles are common substructures in bioactive small molecules, synthetic methods for their derivatization are still limited. Previously, several enantioselective allylation reactions of benzimidazoles were reported that functionalize the nucleophilic nitrogen atom. Herein we describe a reversal of this inherent selectivity toward N-allylation by using electrophilic N-OPiv benzimidazoles with readily available 1,3-dienes as nucleophile precursors. This CuH-catalyzed approach utilizes mild reaction conditions, exhibits broad functional-group compatibility, and exclusively forms the C2-allylated product with excellent stereoselectivity.