N-Heterocyclic Carbene-Cu-Catalyzed Enantioselective Allenyl Conjugate Addition

Org Lett. 2018 Nov 2;20(21):6896-6900. doi: 10.1021/acs.orglett.8b03029. Epub 2018 Oct 16.

Abstract

A catalytic enantioselective conjugate addition with commercially available allenylboronic acid pinacol ester as nucleophile promoted by a chiral copper complex of N-heterocyclic carbene (NHC) is disclosed. This process constitutes an unprecedented instance of the conjugate addition that introduces an allenyl group into α,β-unsaturated carbonyl compounds, affording products that are otherwise difficult to access in up to 92% yield, >98% allenyl addition selectivity and 96:4 enantiomeric ratio. DFT calculations were performed to elucidate the origins of enantioselectivity.

Publication types

  • Research Support, Non-U.S. Gov't