ACDC-Epoxidation

Significance

The authors employ asymmetric counteranion-directed catalysis (ACDC) for the enantioselective organocatalytic epoxidation of di- and trisubstituted α,β-unsaturated aldehydes 1. Dibenzylammonium salt 2 as catalyst together with tert-butyl hydroperoxide (3) as oxidant convert 1,2-disubstituted enals and β,β-disubstituted α,β-unsaturated aldehydes 1 into the corresponding 2,3-epoxyaldehydes 4 with high diastereo- and enantioselectivities.