First asymmetric synthesis of 4-piperidones. Preparation of optically active diastereomers of 1-α-phenylethyl-2-methyl-4-piperidone

Abstract

The fundamental possibility of carrying out the asymmetric synthesis of 4-piperidones on the basis of the transamination of 1-substituted 2-methyl-4-piperidone methiodides by optically active α-phenylethylamine was demonstrated; the optical yield of the asymmetric transamination is 50%. The occurrence of asymmetric synthesis was confirmed by the isolation of enantiomers of 2-methyl-4-piperidol by reduction of the individual diastereomers of 1-α-phenyl-ethyl-2-methyl-4-piperidone to the corresponding 4-piperidols with subsequent removal of the chiral substituent attached to the nitrogen atom. © 1986 Plenum Publishing Corporation.