Recyclable copper catalysts based on imidazolium-tagged C2-symmetric bis(oxazoline) and their application in D–A reactions in ionic liquids

Zhi Ming Zhou*, Zhi Huai Li, Xiao Yan Hao, Xiao Dong, Xin Li, Li Dai, Ying Qiang Liu, Jun Zhang, Hai feng Huang, Xia Li, Jin liang Wang

*此作品的通讯作者

科研成果: 期刊稿件文章同行评审

19 引用 (Scopus)

摘要

Functional imidazolium ionic liquids have been developed as a new class of versatile catalysts. C2-symmetric and unsymmetric imidazolium-tagged bis(oxazoline) ligands were prepared, and the anions of the ligands were altered by ion-exchange reactions. The catalysts based on the new ligands and Cu(OTf)2 were applied in asymmetric Diels–Alder reactions between N-acryloyl/N-crotonoyloxazolidinones 15 and 1,3-cyclohexandiene/cyclopentadiene 16 in different ionic liquids and in dichloromethane (DCM). The catalysts achieved a high level of activity and enantioselectivity, as well as good recyclability: cycloadduct (S)-17ab was attained at 98% conversion and 97% ee in [Bmim]NTf2. Moreover, the catalyst could be recycled 20 times without an obvious loss of activity or enantioselectivity. By comparison, we deduced that the C2 symmetry of the new ligands was crucial for obtaining high ee values. Toxicity studies of the ligands were performed for the first time.

源语言英语
页(从-至)2963-2971
页数9
期刊Green Chemistry
13
10
DOI
出版状态已出版 - 10 1月 2011

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