Well-Defined Chiral Copper NHC Complex in Asymmetric Conjugated β-Borylation and One-Pot Metathesis-Asymmetric β-Borylation.

Highly stereoselective conjugate β-borylation, using a new chiral NHC-based copper catalyst, has been achieved. The chiral NHC copper complex was prepared in gram scale and showed high enantioselectivity and activity (up to 10 000 turnovers at 100 ppm of catalyst loading). This method was employed in the synthesis of chiral β-borylated ester from simple unconjugated alkenes though unprecedented one-pot cross metathesis-asymmetric borylation sequence.