Cobalt-Catalyzed Diastereo- and Enantioselective Hydroalkenylation of Cyclopropenes with Alkenylboronic Acids

Abstract

Catalytic diastereo- and enantioselective hydroalkenylation of 3,3-disubstituted cyclopropenes with readily accessible alkenylboronic acids, promoted by a chiral phosphine/Co complex, is presented. Such a process constitutes the unprecedented and direct introduction of a wide range of alkenyl groups onto the cyclopropane motif to afford multisubstituted cyclopropanes in up to 95 % yield with greater than 95:5 d.r. and 99:1 e.r. Functionalization of the products delivered enantioenriched cyclopropanes that are otherwise difficult to access.

Keywords: boronic acids; cobalt; enantioselectivity; reaction mechanisms; small ring systems.