| Autor: |
Demers-Carpentier V; C3V and Department of Chemistry, Laval University, Québec, Canada G1V 0A6., Rasmussen AM, Goubert G, Ferrighi L, Dong Y, Lemay JC, Masini F, Zeng Y, Hammer B, McBreen PH |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of the American Chemical Society [J Am Chem Soc] 2013 Jul 10; Vol. 135 (27), pp. 9999-10002. Date of Electronic Publication: 2013 Jun 27. |
| DOI: |
10.1021/ja403955k |
| Abstrakt: |
Chirally modified Pt catalysts are used in the heterogeneous asymmetric hydrogenation of α-ketoesters. Stereoinduction is believed to occur through the formation of chemisorbed modifier-substrate complexes. In this study, the formation of diastereomeric complexes by coadsorbed methyl 3,3,3-trifluoropyruvate, MTFP, and (R)-(+)-1-(1-naphthyl)ethylamine, (R)-NEA, on Pt(111) was studied using scanning tunneling microscopy and density functional theory methods. Individual complexes were imaged with sub-molecular resolution at 260 K and at room temperature. The calculations find that the most stable complex isolated in room-temperature experiments is formed by the minority rotamer of (R)-NEA and pro-S MTFP. The stereodirecting forces in this complex are identified as a combination of site-specific chemisorption of MTFP and multiple non-covalent attractive interactions between the carbonyl groups of MTFP and the amine and aromatic groups of (R)-NEA. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
|
