Asymmetric Epoxidation Catalyzed by α,α-Dimethylmorpholinone Ketone. Methyl Group Effect on Spiro and Planar Transition States

Asymmetric epoxidation of olefins by using an α,α-dimethylmorpholinone-containing chiral ketone catalyst (4) has been investigated. This ketone, which has the combined features of several previously studied catalysts, is an effective catalyst for trans- and trisubstituted olefins, and up to 97% ee has been achieved. The α,α-dimethyl group has significant impact on spiro and planar transition states.