Cascade Reactions of Amphoteric Amino Aldehydes

Significance

An unusual Baylis-Hillman reac-tion of amphoteric amino aldehydes via an aza-­Michael-aldol cascade is reported. Using a secondary amine-Brønsted acid catalyst combination, the authors obtained compounds 1. The use of aprotic solvents which slow down the dissociation of dimer 2 was crucial. The proposed mechanism begins with the activation of α,β-unsaturated aldehyde by iminium catalysis. This electrophile initiates a domino process within the amphoteric molecule leading to products 1.