Reaction of cyclohexanones imines with substituted nitroolefins. New synthesis of tetrahydroindole derivatives

The Michael-type addition of cyclohexanones imines, reacting as their secon dary enamine tautomers. to beta-substituted nitroolefins is followed by a c yclization reaction with elimination of the nitro group to afford substitut ed tetrahydroindoles. When a 2-methylcyclohexanone imine is reacted, an une xpected inversion of the regioselectivity is observed when compared with be ta-substituted ethylenic eaters. thus allowing to obtain also substituted t etrahydroindoles (C) 1999 Published by Elsevier Science Ltd. All rights res erved.