Asymmetric synthesis and chromatographic resolution of all four stereomers of the alpha,beta-propanoleucine.
The paper describes the first synthesis of the enantiomerically pure cis-alpha,beta-propanoleucines 6c and 6d by means of asymmetric Strecker synthesis. Furthermore, an improved procedure for the preparation of the stereomeric trans compounds 6a and 6b is proposed. Finally, the four feasible stereomeric alpha,alpha-quaternary-alpha-amino acids are resolved on a penicillamine based chiral stationary phase allowing the determination of ee values ranging from 92.9% to > 98%.
Bisel
P
P
Lehrstuhl für Pharmazeutische Chemie, Universität Freiburg, Germany.
Breitling
E
E
Schlauch
M
M
Volk
F J
FJ
Frahm
A W
AW
D002851:Chromatography, High Pressure Liquid; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007930:Leucine / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D009682:Magnetic Resonance Spectroscopy; D013237:Stereoisomerism
D007202:Indicators and Reagents; D007930:Leucine