Preparation of 3,5-Disubstituted Pyrazoles and Isoxazoles from Terminal Alkynes, Aldehydes, Hydrazines, and Hydroxylamine
作者:Ryo Harigae、Katsuhiko Moriyama、Hideo Togo
DOI:10.1021/jo4027116
日期:2014.3.7
provided the corresponding 3,5-disubstituted pyrazoles or isoxazoles in good yields with high regioselectivity, through the formations of propargyl secondary alkoxides and α-alkynyl ketones. The present reactions are one-pot preparation of 3,5-disubstituted pyrazoles from terminal alkynes, aldehydes, molecular iodine, and hydrazines, and 3,5-disubstituted isoxazoles from terminal alkynes, aldehydes
末端炔与正丁基锂的反应,然后与醛的反应,再用分子碘处理,然后肼或羟胺以高收率提供相应的3,5-二取代的吡唑或异恶唑,其高区域选择性通过形成炔丙基仲醇盐和α-炔基酮。本反应是从末端炔烃,醛,分子碘和肼一锅制备3,5-二取代吡唑,和从末端炔烃,醛,分子碘和羟胺一锅制备3,5-二取代异恶唑。