Diastereoselective total synthesis of 3,6-disubstituted piperidine alkaloids, (3R,6S)-epi-pseudoconhydrine and (3R,6R)-pseudoconhydrine

Diastereoselective total synthesis of 3,6-disubstituted piperidine alkaloids, epi-pseudoconhydrine (1) and pseudoconhydrine (2) has been developed starting from enantiopure (S)-epichlorohydrin. The key steps in the synthesis of these alkaloids involved α-aminobutyrolactone ring opening with N,O-dimethyhydroxyl amine followed by a Grignard reaction and cascade debenzylation-reductive aminative cyclization under hydrogenation conditions. High de was obtained in the synthesis of epi-pseudoconhydrine (1).