By treatment with a base such as sodium methoxide or surprisingly lithium aluminium hydride monocycloadducts 1a - c afforded the corresponding oximes 2a - c which were oxidized to ketones 3a - c by the Dess-Martin method. The same ketones 3a - c are obtained by reductive ring opening of 1a - c with Raney-Ni. Monocycloadducts 1d - h also have oximes 2d - h upon treatment with the same bases, but complex reaction mixtures were obtained when oximes 2d - h were subjected to oxidation or monocycloadducts 1d - h were subjected to reduction with Raney-Ni.