DIASTEREOSELECTIVE SYNTHESIS OF trans-4-ARYLPIPERIDINE-3-CARBOXYLIC ACID DERIVATIVES FROM 4-ARYL-1,4-DIHYDROPYRIDINE

摘要

A convenient procedure for the preparation of trans-3,4-disubstituted piperidines from 4-aryl-1,4-dihydropyridine is described.The diastereo-selective synthesis of an unnatural amino acid,trans-4-arylpiperidine-3-carboxylic acid,and is derivatives is exemplified.The key steps include the construction of a trans-3,4-disubstuted piperidine moiety in compound (5),N-methyl carbamate of trans-4-aryl-piperidine-3-carboxylic acid,from 4-aryl-1,4-dihydropyridine-3-carboxylic acid methyl ester (2) via hydrogenation,reduction,and hydrolysis.Reduction of acid (5) with lithium aluminum hydride or with sodium borohydride provided the corresponding carbinol (7)or(8).