An Intramolecular Wittig Approach toward Heteroarenes: Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes
作者:Pankaj V. Khairnar、Tsai-Hui Lung、Yi-Jung Lin、Chi-Yi Wu、Srinivasa Rao Koppolu、Athukuri Edukondalu、Praneeth Karanam、Wenwei Lin
DOI:10.1021/acs.orglett.9b01395
日期:2019.6.7
α-Halohydrazones/ketoximes are transformed into trisubstituted pyrazoles/disubstituted isoxazoles by treatment with phosphine, acyl chloride, and a base. Mechanistic investigations revealed the in situ formation of azo/nitroso olefin intermediates which underwent a tandem phospha-Michael/N- or O-acylation/intramolecular Wittig reaction to afford the heteroarenes in moderate to good yields. Further
Efficient and Regioselective One-Pot Synthesis of 3-Substituted and 3,5-Disubstituted Isoxazoles
作者:Shibing Tang、Jinmei He、Yongquan Sun、Liuer He、Xuegong She
DOI:10.1021/ol901626n
日期:2009.9.3
A series of 3-substituted and 3,5-disubstitutedisoxazoles have been efficiently synthesized in moderate to excellent yields by the reaction of N-hydroxyl-4-toluenesulfonamide with α,β-unsaturated aldehydes/ketones. This novel strategy is associated with readily available starting materials, mild conditions, high regioselectivity, and wide scope.
Complementary regioselective synthesis of 3,5-disubstituted isoxazoles from ynones
作者:Xiaochen Liu、Dongsub Hong、Zhigang She、William H. Hersh、Barney Yoo、Yu Chen
DOI:10.1016/j.tet.2018.09.043
日期:2018.11
dehydration. The two routes are not only both highly regioselective, but also complementary to each other as a pair of regioisomeric 3,5-disubstituted isoxazoles are readily prepared from one single ynone substrate. The efficiency of the two routes are further evaluated and demonstrated in the synthesis of three representative 3,5-disubstituted isoxazoles.
A palladium-catalyzed oxidative aminocarbonylation of alkynone O-methyloximes with amines and CO using PEG-400 as an environmentally benign medium was accomplished.
使用PEG-400作为环境友好介质,通过钯催化氧化氨基羰基化合物与胺和CO反应的方法成功实现。
Synthesis of 3,5-diarylisoxazoles under solvent-free conditions using iodobenzene diacetate
Abstract A simple and efficient method has been developed for conversion of chalcone oximes to 3,5-diaryl isoxazoles in excellent yields under solvent-free conditions. The synthesized compounds were characterized by infrared spectroscopy, 1 H NMR, 13 C NMR and HRMS.
摘要研究了一种简单有效的方法,可在无溶剂条件下以优异的收率将查尔酮肟转化为3,5-二芳基异恶唑。合成的化合物通过红外光谱,1 H NMR,13 C NMR和HRMS进行表征。