Advances in asymmetric epoxidation of a,b-unsaturated carbonyl compounds: the organocatalytic approach

The area of asymmetric epoxidation of ,-unsaturated carbonyl compounds is extensively studied owing to the synthetic importance of enantiomerically enriched epoxides as building blocks and products of pharmaceutical interest. In this review a comprehensive overview of the advances on the enantioselective organocatalytic methodologies for the epoxidation of ,-unsaturated carbonyl compounds is presented. Dealing with the use of small organic molecules as catalysts, enantioselective organocatalysis is a flourishing new field of asymmetric synthesis to be considered complementary and in some examples alternative to metal complexes/chiral ligands and enzymatic approaches. In this context, new methodologies of enantioselective epoxidation of ,-unsaturated ketones and aldehydes have been recently elaborated. The noteworthy features of these protocols focus on straightforwardly available, low cost, easy to handle organic catalysts and operational simplicity.