Metal-catalyzed [6 + 3] cycloaddition of tropone with azomethine ylides: a practical access to piperidine-fused bicyclic heterocycles.

Honglei Liu, Yang Wu, Yan Zhao, Zhen Li, Lei Zhang, Wenjun Yang, Hui Jiang, Chengfeng Jing, Hao Yu, Bo Wang, Yumei Xiao, Hongchao Guo

Index: J. Am. Chem. Soc. 136(6) , 2625-9, (2014)

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Abstract

The first metal-catalyzed [6 + 3] cycloaddition of tropone with azomethine ylides has been developed. With the use of a chiral ferrocenylphosphine-copper(I) complex as the catalyst, the asymmetric variant of the [6 + 3] cycloaddition has also been successfully achieved. The reactions proceeded smoothly under mild conditions, affording piperidine-fused bicyclic heterocycles in moderate to high yields with good to excellent diastereo- and enantioselectivies. The procedures are operationally simple and the catalysts are cheap and readily accessible, thus providing a practical approach to piperidine-fused bicyclic heterocycles.