Cobalt‐Catalyzed Enantioselective Alkenylative Cyclization of 1,6‐Allenynes

Transition metal‐catalyzed cascade cyclization of allenynes is regarded as an efficient approach for the synthesis of versatile cyclic frameworks. However, catalytic asymmetric cascade cyclizations of allenynes are still uncommon. Herein, we present the first cobalt‐catalyzed enantioselective alkenylative cyclization of 1,6‐allenynes with readily available alkenylboronic acids, providing five‐membered carbo‐ and heterocycles with high efficiency (up to 97% yield), broad substrate scope, and moderate to good enantioselectivities (up to 95:5 er).