Asymmetric Reactions Catalyzed by Chiral Metal Complexes. LVII. Synthesis of Efficient Chiral Bisphosphine Ligands, Modified DIOPs, (4R,5R)-4-(Diaryl- or dialkylphosphino)methyl-5-(diarylphosphino)methyl-2,2-dimethyl-1,3-dioxolanes, and Their Use in Rhodium(I)-Catalyzed Asymmetric Hydrogenations
| Autor: | Mitsuo Chiba, Kazuo Achiwa, Toshiaki Morimoto |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
chemistry.chemical_classification
Stereochemistry Asymmetric hydrogenation Enantioselective synthesis chemistry.chemical_element General Chemistry General Medicine Medicinal chemistry Catalysis Rhodium chemistry.chemical_compound Dicarboxylic acid chemistry Drug Discovery Phenyl group Itaconic acid Phosphine |
| Zdroj: | Chemical and Pharmaceutical Bulletin. 41:1149-1156 |
| ISSN: | 1347-5223 0009-2363 |
| Popis: | Modified DIOPs, (4R, 5R)-4-(diaryl- or dialkylphosphino)methyl-5-(diarylphosphino)methyl-2, 2-dimethyl-1, 3-dioxolanes, were prepared on the basis of our design concept, and used as ligands for the rhodium(I)-catalyzed asymmetric hydrogenations of ketopantolactone, itaconic acid, demethyl itaconate, and β-aryl-substituted itaconic acid derivatives. A neutral rhodium(I)-complex of (4R-trans)-dicyclohexyl[[5-[(diphenylphosphino)methyl]-2, 2-dimethyl-1, 3-dioxolan-4-yl]methyl]phosphine (DIOCP) bearing both a dicyclohexylphosphino group and a diphenylphosphino group was found to be a more efficient catalyst than the original DIOP in the asymmetric hydrogenation of ketopantolactone. Modified DIOPs bearing electron-donating groups at their para positions were efficient ligands for the rhodium(I)-catalyzed asymmetric hydrogenations of itaconic acid and its derivatives; in particular, (4R-trans)-[(2, 2-dimethyl-1, 3-dioxolane-4, 5-diyl)bis(metylene)]bis[bis(4'-methoxy-3', 5'-dimethylphenyl)phosphine] (MOD-DIOP) bearing both a p-methoxy group and two m, m'-methyl groups on each phenyl group showed much higher enantioselectivity and catalytic activity than DIOP. |
| Databáze: | OpenAIRE |
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