Copper-Catalyzed Asymmetric Reduction of β,β-Disubstituted Alkenylboramides

Org Lett. 2019 Nov 1;21(21):8779-8782. doi: 10.1021/acs.orglett.9b03400. Epub 2019 Oct 18.

Abstract

A highly enantioselective copper-catalyzed reduction of β,β-disubstituted alkenylboron compounds was developed using hydrosilane. The copper hydride catalyst coordinated with chiral Josiphos ligand efficiently discriminated β-geminal substituents to generate corresponding β-chiral alkylboramides with excellent enantioselectivities up to 99% ee. The enantioselective reduction protocol provides a facile approach to β-chiral alkylboron compounds with less sterically discriminating substituents and spans a wide substrate range including aryl-substituted borylalkenes with effective functional group tolerance.