Three-component organocascade kinetic resolution of racemic nitroallylic acetates via sequential iminium/enamine asymmetric catalysis

Nitroallylic acetates 1a-f have been kinetically resolved via an asymmetric three-component coupling that involves indoles, acrolein, and nitroolefin allylic acetates and is mediated by the chiral catalyst 2 (5 mol %). The reactions proceed via iminium/enamine cascade catalysis. Both recovered starting substrates and reaction products are typically obtained in high chemical yield and in good to excellent enantiopurity (79-95% ee for 1a-f and 83-99% ee for 3a-n). For the first time, a highly efficient three-component, organocascade kinetic resolution has been demonstrated.