Microwave and Classical Activation of Solvent-Free Reactions of NIsopropyl Arylidene Amines with Alkyl Cyanoacetates

Neat imine 1a with alkylcyanoacetate 2 leads to new cyclohexenes by Michael-Michael initiated ring closure reaction at RT or under classical heating. Surprisingly, this cyclohexene is not formed under microwave. This is the first example of a reaction working under classical activation and not under microwaves. A mechanism and an explanation are proposed.