A Chiral 6-Membered N-Heterocyclic Carbene Copper(I) Complex That Induces High Stereoselectivity

A chiral 6-membered annulated N-heterocyclic (6-NHC) copper complex that catalyzes beta-borylations with high yield and enantioselectivity was developed. The chiral 6-NHC copper complex is easy to prepare on the gram scale and is very active, showing 10 000 turnovers at 0.01 mol % of catalyst without significant decrease of enantioselectivity and with useful reaction rates.