The role of the nitrogen atom in the hydrogenation of piperidinones and methylenepiperidines

Abstract

Dimethylpiperidinones and dimethylmethylenepiperidines have been hydrogenated over several Group 8, 9 and 10 transition metal catalysts and the stereochemistry of the products compared with those of the carbocyclic analogues. The results obtained suggest that intramolecular interactions between the nitrogen lone pair and the unsaturated bond play a major role in determining the stereochemistry of hydrogenation.