Divalent Samarium Triflate Mediated Stereoselective Pinacol Coupling of Planar Chiral Phosphanyl and Phosphoryl Ferrocenecarbaldehyde
| Autor: | Kenichi Ogata, Shin-ichi Fukuzawa, Minoru Kato, Kenta Shimizu, Ichiro Oura |
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| Rok vydání: | 2008 |
| Předmět: |
chemistry.chemical_classification
Pinacol coupling reaction Stereochemistry Pinacol Organic Chemistry Asymmetric hydrogenation Enantioselective synthesis chemistry.chemical_element Aldehyde Medicinal chemistry Coupling reaction Samarium chemistry.chemical_compound chemistry Physical and Theoretical Chemistry Enantiomeric excess |
| Zdroj: | European Journal of Organic Chemistry. |
| ISSN: | 1099-0690 1434-193X |
| Popis: | The pinacol coupling reaction of (Rp)-2-diphenylphosphanyl ferrocenecarbaldehyde (1) was smoothly mediated by divalent samarium triflate to give (R,R)-diol 2a predominantly, whereas the use of samarium(II) iodide resulted in low selectivity as described in the previous literature. In contrast, the coupling reaction of (Rp)-2-diphenylphosphoryl ferrocenecarbaldehyde (3) with Sm(OTf)2 gave the (S,S)-diol as the major isomer, which was the opposite stereochemistry of that obtained in the reaction with 1. The rhodium complexes of diphosphanes 2a were good catalysts for the asymmetric hydrogenation of α-acetamidocinnamic acid, and the product was obtained quantitatively with up to 92 % ee. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) |
| Databáze: | OpenAIRE |
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