Catalytic Asymmetric Hydrogenation of N-Iminopyridinium Ylides:  Expedient Approach to Enantioenriched Substituted Piperidine Derivatives

We have developed an efficient catalytic enantioselective hydrogenation of pyridine derivatives. Enhanced reactivity was possible by an optimization of the electronic properties of the catalyst through ligand modification. This methodology shows the particular reactivity of N-iminopyridinium ylides that provides access to substituted piperidines in good enantiomeric excesses.