ASYMMETRIC EPOXIDATION OF α,β-UNSATURATED KETONES WITH HYDROGEN PEROXIDE CATALYZED BY AXIALLY CHIRAL GUANIDINE BASE

The enantioselective epoxidation of alpha,beta-unsaturated ketones with hydrogen peroxide was demonstrated using axially chiral guanidine as a base catalyst. Hydrogen peroxide can be utilized as a cost-effective and atom-efficient oxidant in the present catalytic epoxidation even under heterogeneous conditions. The newly developed axially chiral guanidine base bearing an additional central chirality functions as an efficient catalyst to provide epoxides in 51-65% ee.