Reaction of Cyclohexanones Imines with Substituted Nitroolefins. New Synthesis of Tetrahydroindole Derivatives

Article abstract of DOI:10.1016/S0040-4039(99)00708-X

The Michael-type addition of cyclohexanones imines, reacting as their secondary enamine tautomers, to β-substituted nitroolefins is followed by a cyclization reaction with elimination of the nitro group to afford substituted tetrahydroindoles. When a 2-methylcyclohexanone imine is reacted, an unexpected inversion of the regioselectivity is observed when compared with β-substituted ethylenic esters, thus allowing to obtain also substituted tetrahydroindoles. - Keywords: Imines; Michael reactions; Regioselection; Indoles