Diamide 8, prepared by treatment of 3-methylglutaric acid (1) with 4 (R)-MCTT (5) in the presence of DCC in pyridine, was subjected to aminolysis with 1 equiv of piperidine in CH2C12 at-30 “C to give a mixture of diastereomers 9a and 10a in a 88: 12 ratio. Compound 9a, separated by silica gel column chromatography, was treated with various nucleophiles to give optically pure bifunctional synthons lla-k in high yields. Highly selective chiral ...
