Copper-catalyzed Conjugate Additions of Alkylboranes to Aryl α,β-Unsaturated Ketones

Conjugate addition of alkylboron compounds (alkyl-9-BBN) to aryl alpha,beta-unsaturated ketones proceeded in the presence of a catalytic amount (10 mol %) of [(IPr)CuCl] and t-BuOK. The alkylboranes are available through alkene hydroboration, and thus the overall process represents a reductive conjugate addition of alkenes to enone derivatives. A variety of functional groups are tolerated in both the alkenes and the alpha,beta-unsaturated ketones.