SYNTHESIS OF METHYL 6-ARALKYL-2,5-DIKETOPIPERIDINE-3-CARBOXYLATES AS SYNTHONS OF CONFORMATIONALLY CONSTRAINED PSEUDOPEPTIDES

Article abstract of DOI:10.1016/0040-4039(91)80834-S

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