The palladiumcatalyzed one-pot synthesis of isoxazoles and pyrazoles from aryl iodides, terminal alkynes, chromium hexacarbonyl and hydroxylamine hydrochloride or aqueous hydrazine solution is described. The Sonogashira carbonylative coupling intermediate was trapped in situ by hydroxylamine hydrochloride or aqueous hydrazine to deliver isoxazoles or pyrazoles, respectively, in high yields. This efficient
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-disubstitutedisoxazolesfrom terminal alkynes, aldehydes
TBAI-catalyzed intramolecular annulation of chalcone oximes toward isoxazoles
作者:Ablimit Abdukader、Yadong Sun、Zengpeng Zhang、Chenjiang Liu
DOI:10.1016/j.catcom.2017.11.008
日期:2018.2
A TBAI-catalyzed intramolecular annulation of chalcone oximes toward isoxazoles was developed, providing 3,5-diarylisoxazoles in good yields. Functional groups such as methoxy, ethyoxyl, chloro, bromo, fluoro and nitro were well tolerated in this reaction. Notably, the reaction ran under metal-free in water.