Alumina-Promoted Copper-Catalyzed Hydroboration of Alkynes

Abstract

AbstractAlumina was found to activate Cu(I) catalysts in hydroboration of alkynes. This allowed to develop a simple and efficient protocol for hydroboration of alkynes with B2Pin2 using inexpensive CuCl/PPh3 catalytic system. The approach does not require moisture-sensitive activators and stepwise preparation of ‘activated’ Cu complex. The developed conditions were applied to the preparation of β-styrylboronates from terminal and internal alkynes with excellent regio- and stereoselectivity. The procedure can also be extended to other terminal alkynes by the appropriate choice of ligand.