Highly Enantioselective Organocatalytic Carbonyl-Ene Reaction with Strongly Acidic,Chiral Bronsted Acids as Efficient Catalysts

摘要

Asymmetric Bronsted acid catalysis has emerged as a powerful tool in organic synthesis.In particular,chiral phosphoric acids have become established as useful organocatalysts for highly enantioselective transformations.The central role performed by the phosphoric acids in such reactions is the activation of the electrophile by catalytic protonation to form an intermediary ion pair composed of the activated(proton-ated)electrophile and a chiral phosphate counterion.This counterion induces the high enantioselectivities observed.Various enantioselective transformations of aldimines and ketimines have been carried out by applying this strategy.