A first case of asymmetric catalysis induced by metal-free bisoxazolines

摘要

Metal-free bisoxazolines catalyze the Diels-Alder reaction of N-substituted maleimides with anthrone derivatives leading to products in excellent yields and enantioselectivities up to 70%. A mechanism relying on Bronsted-base catalysis is assumed to be involved with formation of an ion pair between the protonated catalyst and the anthrone enolate, which acts as a diene.