MIMIRC Reactions of nitromethane with electrophilic alkenes in solvent-free reactions under microwave irradiation

New highly functionalized cyclohexenes 3a-h or 4a-i (after demethoxycarbonylation or deamidation at C-3) are obtained from the reaction of nitromethane 1 with electrophilic alkenes 2a-i RCH=C(CN)(Y) with Y=CO2R', CN, CONH2 in a solvent-free reaction catalyzed by piperidine at room temperature or under focused microwave irradiation after a few min. The mechanism involves a double Michael addition followed by intramolecular ring closure (MIMIRC reaction). The reaction is diastereoselective (two diastercoisomers only). In some cases, non-cyclized intermediates have been isolated. Stoechiometric amounts of piperidine promote the demethoxycarbonylation of 3. When Y is an amide group, a first example of chemical deamidation is observed. (C) 2002 Elsevier Science Ltd. All rights reserved.