Enantioselective Copper‐Catalyzed Three‐Component Carboboronation of Allenes: Access to Functionalized Dibenzo [b,f][1,4]oxazepine Derivatives

A copper‐catalyzed enantioselective three‐component difunctionalization of allenes with seven‐membered cyclic imines and bis(pinacolato)diboron (B2(Pin)2) to approach functionalized dibenzo[b,f][1,4]oxazepine derivatives is developed. The chiral products are obtained in up to 81% yield, >20:1 dr, and 98% ee when either a chiral diphosphine ligand or a chiral ferrocenyl‐based P,N‐ligand is used. Furthermore, the reaction exhibits reversed diastereoselectivities when the chiral diphosphine ligand and the chiral P,N‐ligand are used respectively.