Iridium Catalyzed Enantioselective Hydrogenation of N-Iminopyridinium Ylides: Mechanistic Insights

Mechanistic insights of the efficient iridium catalyzed asymmetric hydrogenation of N-iminopyridinium ylides are reported.Using NMR and mass spectrometry, the nature of the pre-catalyst and role of iodine was studied.The effect of solvent as well as an extensive ligand screening is presented.Deuteration experiments also show that C-H(D) insertion pathways occur in competition with the hydrogenation process.