Copper(II)/Silver(I)-Catalyzed Sequential Alkynylation and Annulation of Aliphatic Amides with Alkynyl Carboxylic Acids: Efficient Synthesis of Pyrrolidones
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- 作者：Jitan Zhang ; Danyang Li ; Hui Chen ; Binjie Wang ; Zhanxiang Liu and Yuhong Zhang
- 关键词：alkynylation/annulations ; C&ndash ; H activation ; copper ; decarboxylation ; pyrrolidones
- 刊名：Advanced Synthesis & Catalysis
- 出版年：2016
- 出版时间：March 3, 2016
- 年：2016
- 卷：358
- 期：5
- 页码：792-807
- 全文大小：707K
- ISSN：1615-4169
文摘
A highly efficient protocol for the synthesis of pyrrolidones by the copper-catalyzed alkynylation/annulation of aliphatic amides with alkynyl carboxylic acids is discussed in this paper. A broad range of easily accessible alkynyl carboxylic acids were introduced at the β-methyl group of aliphatic amides with the assistance of an 8-aminoquinolyl auxiliary group via decarboxylation to achieve the subsequent cyclic CN bond formation within one hour. High selectivity of β-methyl groups over methylene groups was observed, and the extension of this catalytic system to the activation of methylene CH bonds failed. The substrates with two different groups at the -position of the aliphatic amides lead to the formation of diastereoisomers which is determined by 1H NMR spectroscopy. The initially produced products with Z-configurations can be easily transformed to the corresponding products with E-configurations by the treatment with dilute p-toluenesulfonic acid after the reaction. This catalytic tandem decarboxylative cyclization provides a new opportunity for the direct functionalization of sp3 CH bonds.