Nine acyclic acetal ketal benzylamines have been synthesized and their cyclization reactions in acidic methanol have been examined. In three cases, bicyclic amines-a tropane, a granatanine, and a homotropane-are formed. In five cases, cyclic iminium salts which do not undergo further bicyclization are formed, and these salts were reduced to afford three 2, 5-disubstituted pyrrolidines and two substituted piperidines. In the one case requiring ...