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Hyperbranched polyethylene-supported L-proline: a highly selective and recyclable organocatalyst for asymmetric aldol reactions
| Content Provider | Semantic Scholar |
|---|---|
| Author | Wang, Song Liu, Pingwei Wang, Wen-Jun Zhang, Zhiguo Li, Bo-Geng |
| Copyright Year | 2015 |
| Abstract | A novel hyperbranched polyethylene (HBPE)-supported L-proline has been developed via a bottom-up copolymerization strategy. Copolymerization of ethylene and a protected proline acrylate comonomer with cationic Pd-diimine catalysts was conducted, followed by de-protection of the proline groups. Well-defined HBPE copolymers having molecular weights (MWs) of 10.3–50.3 kDa and 3.2–15.6 L-proline molecules per HBPE polymer chain were synthesized. The effects of the L-proline amount and HBPE MW on the catalyst performance were studied. The HBPE catalysts were efficient in asymmetric aldol reactions of p-nitrobenzaldehyde (p-NBA) or benzaldehyde derivatives with cyclohexanone. High p-NBA conversions of up to 98% and excellent product selectivities with anti/syn = 98/2 and ee > 99% were achieved. Moreover, the HBPE catalysts could be easily recovered by adding water into the product. The recovered catalysts could be reused multiple times with only a slight decline in reactivity and selectivity. |
| Starting Page | 3798 |
| Ending Page | 3805 |
| Page Count | 8 |
| File Format | PDF HTM / HTML |
| DOI | 10.1039/C5CY00250H |
| Volume Number | 5 |
| Alternate Webpage(s) | http://www.rsc.org/suppdata/c5/cy/c5cy00250h/c5cy00250h1.pdf |
| Alternate Webpage(s) | https://doi.org/10.1039/C5CY00250H |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
