cis and trans 2,3-disubstituted pyrrolidines and piperidines have been prepared stereoselectively by intramolecular conjugate addition of N-substituted gamma-oxygenated-alpha,beta-unsaturated phenyl sulfones. The best cis-selectivities were obtained from the alcohols and the best trans-selectivities from the OTIPS derivatives. (C) 1996 Published by Elsevier Science Ltd