Enantioselective Cycloadditions with α,β-Disubstituted Acrylimides.

The use of N-H imide templates provides a solution to the problem of rotamer control in Lewis acid catalyzed reactions of α,β-disubstituted acryloyl imides. Reactions proceed through the s-cis rotamer and with improved reactivity because A1,3 strain is avoided. Enantioselective nitrone, nitrile oxide, and Diels−Alder cycloadditions demonstrate the principle.