摘要:
Catalytic hydrogenation of the 4-ketoesters 1a,b or 2a,b and their 5R-enantiomers, obtained from the corresponding Z-L- and Z-D-amino acid halomethyl ketones, directly leads to the methyl 6-aralkyl-2,5-diketopiperidine-3-carboxylates 3a,b and 4a,b and their 6R-enantiomers with high or moderate stereoselectivity at C-3.