Electronically controlled asymmetric cyclopropanation catalyzed by a new type of chiral 2,2′-bipyridine

An optically active atropisomeric 2,2′-bipyridine was synthesized and its copper complex was used in the asymmetric cyclopropanation of para-substituted styrenes with e.e. values up to 86%; the enantioselectivity exhibited a substrate electronic effect in a linear free energy relationship.