Preparation of 3,5-Disubstituted Pyrazoles and Isoxazoles from Terminal Alkynes, Aldehydes, Hydrazines and Hydroxylamine
Ryo Harigae, Katsuhiko Moriyama and Hideo Togo*
*Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan, Email: togofaculty.chiba-u.jp
R. Harigae, K. Moriyama, H. Togo, J. Org. Chem., 2014, 79, 2049-2058.
DOI: 10.1021/jo4027116 (free Supporting Information)
The reaction of terminal alkynes with n-BuLi, and then with aldehydes, followed by the treatment with molecular iodine, and subsequently hydrazines or hydroxylamine provided the corresponding 3,5-disubstituted pyrazoles or isoxazoles in good yields and with high regioselectivity.
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