Asymmetric Synthesis. 39.1 Synthesis of 2-(1-Aminoalkyl)piperidines via 2-Cyano-6-phenyl Oxazolopiperidine

The asym. synthesis of a series of 2-piperidinealkanamines starting from (-)-2-cyano-6-phenyloxazolopiperidine was [i.e., [3R-(3alpha ,5beta ,8abeta )]-hexahydro-3-phenyl-5H-oxazolo[3,2-a]pyridine-5-carbonitrile] (I) as described. LiAlH4 redn. of I followed by hydrogenolysis gave (-)-2-piperidinemethanamine dihydrochloride (II). Addn. of lithium derivs. to the cyano group of I resulted in the formation of intermediate imino bicyclic systems which could be diastereoselectively reduced to substituted diamino alcs. The addn. of an excess of PhLi to I in the presence of LiBr gave a disubstituted amine, the precursor of diphenyl[(2S)-piperidin-2-yl]methanamine. [on SciFinder (R)]