Asymmetric synthesis and chromatographic resolution of all four stereomersof the alpha,beta-propanoleucine

The paper describes the first synthesis of the enantiomerically pure cis-al pha,beta -propanoleucines 6c and 6d by means of asymmetric Strecker synthes is. Furthermore, an improved procedure for the preparation of the stereomer ic trans compounds 6a and 6b is proposed. Finally, the four feasible stereo meric alpha,alpha -quaternary-alpha -amino acids are resolved on a penicill amine based chiral stationary phase allowing the determination of cc values ranging from 92.9% to > 98%.