Rhodium-Catalyzed Addition-Cyclization of Hydrazines with Alkynes: Pyrazole Synthesis via Unexpected C-N Bond Cleavage
Deng Yuan Li, Xiao Feng Mao, Hao Jie Chen, Guo Rong Chen and Pei Nian Liu*
*Institute of Fine Chemicals, East China University of Science and Technology, Meilong Road 130, Shanghai 200237, China, Email: liupnecust.edu.cn
D. Y. Li, X. F. Mao, H. J. Chen, G. Rong, P. N. Liu, Org. Lett., 2014, 16, 3476-3479.
DOI: 10.1021/ol501402p (free Supporting Information)
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A rhodium-catalyzed addition-cyclization of hydrazines with alkynes affords highly substituted pyrazoles under mild conditions. The cascade reaction involves two transformations: addition of the C-N bond of hydrazines to alkynes via unexpected C-N bond cleavage and intramolecular dehydration cyclization.
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