NEW METHOD FOR THE PREPARATION OF (R)-CARNITINE

Abstract

A new method for the preparation of (R)-carnitine (1) has been developed from enantiomerically pure (R)-4-(trichloromethyl)-oxetan-2-one [(R)-2] which was easily obtained from the [2+2]-cycloaddition of ketene and chloral in the presence of catalytic amounts of poly(acryloyl quinidine). The key intermediate, ethyl (R)-3-hydroxy-4-chlorobutyrate [(R)-5], was prepared by ethanolysis of (R)-2 followed by selective bis-dechlorination of ethyl (R)-3-hydroxy-4,4,4-trichlorobutyrate [(R)-3].