ORGN 119 |
| Polysubstituted pyridines are either readily available commercially or can be easily prepared using recent cross-coupling chemistry. Asymmetric hydrogenation of pyridine derivatives thus represents an attractive strategy to access enantioenriched substituted piperidines. We recently published an efficient iridium(III) catalyzed asymmetric hydrogenation methodology of N-iminopyridinium ylides using chiral phosphinooxazolines. We now report the mechanistic insights we gained using NMR and mass spectrometry as well as deuteration experiments. We have discovered that C-H insertion pathways occur in competition with the hydrogenation process. The effect of solvent as well as an extensive ligand screening will be presented.
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Asymmetric Reactions and Syntheses, Metal-Mediated Reactions, Combinatorial, Parallel, and Solid-Phase Chemistry
8:00 PM-10:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster
Division of Organic Chemistry |
