Hexahydro-pentalene and -indene nitroalcohols are obtained by reaction of 3-(4-morpholinyl)-3-buten-2-one with cyclic nitroolefins. With 1-nitro-cyclohexene a [4 + 2] heterocyclization intermediate Is separated, while an unusual product of double addition is obtained from the hexahydro-pentalene derivative in aqueous acidic medium.