A simple and stereospecfic route to 2,6-disubstituted 4-hydroxypiperidines. Synthesis of dendrobate alkaloid (+)-241D and formal synthesis of (-)-indolizidine 167B.

Abstract

The condensation of enantiopure beta-amino esters with beta-ketoesters followed by cyclization and decarboxylation afforded 2,3-dihydro-4-pyridones 3, which were selectively hydrogenated to provide 2,6-disubstituted 4-hydroxypiperdines.