Regioselective synthesis and side-chain metallation and elaboration of 3-aryl-5-alkylisoxazoles
摘要:
A number of 3-aryl-5-alkylisoxazoles have been synthesized in high yields by reacting arylnitrile oxides with free enolate ions regioselectively obtained by metallation of various alkyl methyl ketones with LDA in THF at -78degreesC followed by dehydration. Investigations concerning regioselective side-chain metallation and elaboration of one of them (3-phenyl-5-ethylisoxazole) have also been carried out. (C) 2002 Elsevier Science Ltd. All rights reserved.
Visible-light-mediated generation of nitrile oxides for the photoredox synthesis of isoxazolines and isoxazoles
作者:Thomas D. Svejstrup、Wojciech Zawodny、James J. Douglas、Damon Bidgeli、Nadeem S. Sheikh、Daniele Leonori
DOI:10.1039/c6cc06029c
日期:——
Visible-light photoredox catalysis enables the synthesis of biologically relevant isoxazolines and isoxazoles from hydroxyimino acids. The process shows broad functional group compatibility and mechanisitic and computational studies support a visible-light-mediated...
An environmentally benign synthesis of isoxazolines and isoxazoles mediated by potassium chloride in water
作者:Liuquan Han、Bijun Zhang、Min Zhu、Jie Yan
DOI:10.1016/j.tetlet.2014.02.118
日期:2014.4
An effective and environmentally benign procedure for the synthesis of isoxazolines and isoxazoles has been developed by a cycloaddition of nitrile oxides with alkenes or alkynes in water. In this approach, potassium chloride is first oxidized into chlorine in water by the environmentally friendly oxidant Oxone®, then aldoximes are oxidized into nitrile oxides by the in situ generated hypochlorous
Copper-doped silica cuprous sulfate (CDSCS) as a highly efficient heterogeneous nano catalyst for synthesis of 3,5-disubstituted isoxazoles
作者:M. N. Soltani Rad、S. Behrouz、M. A. Faghihi
DOI:10.1007/s13738-013-0307-4
日期:2014.4
A facile and highly efficient protocol for 1,3-dipolar cycloaddition of in situ generated nitrile oxides with terminal alkynes catalyzed by copper-doped silica cuprous sulfate (CDSCS) as a new and convenient heterogeneous nano catalyst is described. In this protocol, ‘click’ cycloaddition of various structurally diverse alkynes and imidoyl chlorides in the presence of CDSCS and NaHCO3 in a solution of i-PrOH/H2O (1:1, V/V) furnishes the corresponding 3,5-disubstituted isoxazoles in good to excellent yields at room temperature. CDSCS was approved as a chemically and thermally stable nano catalyst that can be recovered and reused for many consecutive trials without considerable decline in its reactivity.
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.