| Autor: |
Na Li, Heng Wang, Xinhua Wan, Zijia Yan, Jie Zhang |
| Rok vydání: |
2015 |
| Předmět: |
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| Zdroj: |
RSC Advances. 5:52410-52419 |
| ISSN: |
2046-2069 |
| Popis: |
Novel optically active polymers containing pendant proline moieties, poly{(−)-L- and (+)-D-proline-[5-(4′-tert-butylphenyl)-3-vinylpyridin-2-yl]amide}, were prepared through radical polymerization of (−)-L- and (+)-D-N-Boc-proline-[5-(4′-tert-butylphenyl)-3-vinylpyridin-2-yl]amide, followed by de-protection of the Boc group. Polarimetry and circular dichroism spectroscopy studies indicated that these polymers took chiral secondary structures. They were employed to catalyze the homogeneous asymmetric aldol reaction of 4-nitrobenzaldehyde with cyclohexanone. The polymeric catalysts showed obviously enhanced reaction rate but slightly reduced enantio-selectivity compared with (−)-L- and (+)-D-proline-[5-(4′-tert-butylphenyl)-3-vinylpyridin-2-yl]amide, the low molar mass counterparts. The lowered enantio-selectivity of the polymeric catalyst might be attributed to the antagonistic action of the configurational chirality of the side-group and the conformational chirality of the polymer backbone on the stereochemistry of aldol reaction. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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