Highly enantioselective aldol reactions catalyzed by reusable upper rim-functionalized calix[4]arene-based l-proline organocatalyst in aqueous conditions

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• 作者：Zheng-Yi Li ; Yuan Chen ; Chong-Qian Zheng ; Yue Yin ; Liang Wang ; ^{liangwang@cczu.edu.cn} ; Xiao-Qiang Sun ; ^{sunxiaoqiang@yahoo.com}
• 关键词：Calix[4]arene ; Proline ; Organocatalysis ; Aldol ; Water
• 刊名：Tetrahedron
• 出版年：2017
• 出版时间：5 January 2017
• 年：2017
• 卷：73
• 期：1
• 页码：78-85
• 全文大小：847 K
• 卷排序：73

文摘

A series of upper rim-functionalized calix[4]arene-based l-Proline derivatives have been synthesized and employed for the enantioselective aldol reactions between cyclic ketones and aromatic aldehydes in the presence of water. Good to excellent yields (up to 96%), enantioselectivities (up to 99% ee), as well as diastereoselectivities (up to 99:1 dr) were obtained under the optimal reaction conditions. Detailed experiments clearly showed that the hydrophobic calixarene platform not only contributed to the good reactivities and enantioselectivities, but also exhibited size-selective catalysis function. Moreover, the organocatalyst can be readily recovered and reused for several runs without significant loss in its enantioselectivity.