Cinchona Alkaloid Squaramide Catalyzed Enantioselective Hydrazination/Cyclization Cascade Reaction of α-Isocyanoacetates and Azodicarboxylates: Synthesis of Optically Active 1,2,4-Triazolines
Mei-Xin Zhao*, Hong-Lei Bi, Hao Zhou, Hui Yang and Min Shi*
*East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, People’s Republic of China, Email: mxzhaoecust.edu.cn, Mshimail.sioc.ac.cn
M.-X. Zhao, H.-L. Bi, H. Zhou, H. Yang, M. Shi, J. Org. Chem., 2013, 78, 9377-9382.
DOI: 10.1021/jo401585v (free Supporting Information)
An efficient enantioselective hydrazination/cyclization cascade reaction of α-substituted isocyanoacetates to azodicarboxylates is catalyzed by a squaramide catalyst derived from Cinchona alkaloid. The reaction affords optically active 1,2,4-triazolines in excellent yields and very good enantioselectivities under mild conditions.
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