STEREOCHEMISTRY AND ISOTOPE EFFECTS IN THE DEUTERIATION OF HINDERED 2,3-DIHYDROFURANS

Article abstract of DOI:10.1016/S0040-4020(01)89987-7

Reductions by deuterium over Pd/C were carried out on a series of dihydrofuran compounds.A stereoselective cis hydrogenation is observed in all cases.The stereochemistry of the dideuteriated products was determined by NOE measurements.According to the steric hindrance of the substituents, deuterium entry is found on the α face or the β face of dihydrofuran ring.The formation of mono- or trideuteriated products may occur from an exchange reaction between adsorbed hydrogenated and semi-hydrogenated species.An unexpected reverse kinetic isotope effect at C4 is observed, showing a very low vibrationnal energy of atomic hydrogen dissolved in the metal lattice.