A novel four-component reaction of diethylamine, an aromatic aldehyde and an alkyl isocyanide with dialkyl acetylenedicarboxylates in the presence of silica gel: an efficient route for the regio- and stereoselective synthesis of sterically congested alken

The 1:1 intermediate generated by the addition of isocyanides to dialkyl acetylenedicarboxylates is trapped by the iminium ion intermediate that forms from the reaction between an aromatic aldehyde and diethylamine. The reactions are completely regio- and stereoselective.