Determination of the absolute configurations of the epimers of the P-chiral phosphine Ph2PCH2CH2P☆Ph(L-(−)-methyl) by use of two-dimensional NMR spectroscopy in combination with a palladium(II) 'reporter complex'
| Autor: | Qiongzhong Jiang, Heinz Rüegger, Luigi M. Venanzi |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Stereochemistry
Chemistry Organic Chemistry chemistry.chemical_element Nuclear magnetic resonance spectroscopy Biochemistry Medicinal chemistry Inorganic Chemistry chemistry.chemical_compound Intramolecular force Materials Chemistry Structural isomer Chelation Epimer Physical and Theoretical Chemistry Spectroscopy Phosphine Palladium |
| Zdroj: | Journal of Organometallic Chemistry. 488:233-240 |
| ISSN: | 0022-328X |
| DOI: | 10.1016/0022-328x(94)00033-9 |
| Popis: | The two epimers of the new P-chiral phosphine Ph 2 PCH 2 CH 2 P ☆ Ph (L-(−)- menthyl ) (1-Rp and 1-Sp) were synthesized by treating Ph2PH with the diastereomerically pure forms of Ph(L-(−)-methyl)CHCH2)P). The palladium(II) complexes [ Pd (( S )-o- C 6 H 4 CHMeNMe 2 )( 1-Rp )][ PF 6 ], 2-Rp and [ Pd (( S )-o- C 6 H 4 CHMeNMe 2 ) ( 1-Sp )[ PF 6 ] , 2-Sp, were obtained by treating the corresponding bisphosphines with [Pd2Cl2((S)-o-CH6H4CHeNMe2)2]. Each of these complex exists in the form of two regioisomers differing in the orientation of the chiral phosphine relative to the C-donor. Constraints from close interligand, intramolecular hydrogen-hydrogen contacts within three of these palladium complexes were detected by two-dimensional NOE spectroscopy, and were used to determine the absolute configurations at the chiral phosphorus centers in the Ph2PCH2CH2PPh(L-(−)-menthyl) isomers. The conformations of the two chelate rings in the more abundant of these isomers were also determined. |
| Databáze: | OpenAIRE |
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