Highly Enantioselective Aza-Henry Reaction of Ketoimines Catalyzed by Chiral N,N′-Dioxide−Copper(I) Complexes
摘要:
The first example of catalytic enantioselective aza-Henry reaction of ketoimines has been realized using a simple chiral N,N'-dioxide-Cu(I) complex as catalyst. It performs well over a range of substrates to give the corresponding products in moderate to good yields (up to 83%) with high enantioselectivities (up to 96% ee).
A novel bifunctional N,N′-dioxide derived from L-prolinamide was employed to catalyze the enantioselective Streckerreaction of a range of N-tosyl ketoimines, and an effective additive was used to improve the reactivity (up to 99 % yield) as well as the enantioselectivity (up to 91 % ee). In addition, a rational transition state was proposed to elucidate the origin of chiral induction in which an S-adduct
Asymmetric Activation oftropos 2,2′-Biphenol with Cinchonine Generates an Effective Catalyst for the Asymmetric Strecker Reaction ofN-Tosyl-Protected Aldimines and Ketoimines