Microwave solvent-free synthesis of nitrocyclohexanols

New nitrocyclohexanols 3a–f are synthesized by a clean and original method from nitromethane 1 and unsaturated ketones 2a–f in the presence of solid potassium fluoride–alumina under solvent-free conditions coupled with microwave irradiation. The reaction involves a double and diastereoselective Michael addition followed by ring closure. Another diastereomer 3′, which differs by the configuration of C-4, is obtained in the presence of piperidine and EtOH at room temperature.