Access to Stereodefined Multifunctionalized β,γ-Unsaturated Ketones via Chemo-, Regio- and Diastereoselective Copper-Catalyzed Diborylation of Cross-Conjugated Enynones^†

Stereodefined β,γ-unsaturated carbonyl compounds are important yet synthetically challenging units in natural products and drugs. Disclosed herein is a mild, rapid copper-catalyzed diborylation reaction of cross-conjugated enynones as a step-economic and modular approach to stereodefined multifunctionalized β,γ-unsaturated ketones by fine control of chemo-, regio-, Z/E and diastereoselectivity. The substrate scope was examined and a possible catalytic cycle was proposed to explain the multifaceted selectivity.