Reductive alkylation of gamma-cyano-alpha,beta-unsaturated ketones. A modified Robinson annulation process to alpha,alpha-disubstituted-beta,gamma-unsaturated cyclohexanone system

Reductive alkylation of various 4-cyano-2-cyclohexenones, readily available from a-cyano ketones via a Robinson annulation process, gave rise to the c orresponding 2,2-disubstituted-3-cyclohexenone derivatives in a completely regioselective manner. Application of this methodology resulted in an effic ient synthesis of the marine natural product nanaimoal in racemic form.