<i>tert</i>-Butyl Nitrite-Mediated Domino Synthesis of Isoxazolines and Isoxazoles from Terminal Aryl Alkenes and Alkynes
作者:Prasenjit Sau、Sourav Kumar Santra、Amitava Rakshit、Bhisma K. Patel
DOI:10.1021/acs.joc.7b00946
日期:2017.6.16
C═N, and C═O bonds from alkenes leading to the direct synthesis of isoxazolines in the presence of tert-butyl nitrite, quinoline, and the Sc(OTf)3 catalyst in DCE at 80 °C has been accomplished. An unprecedented three consecutive C–H functionalizations of two styrenes are involved in this isoxazoline synthesis. In this radical-mediated reaction, one-half of the arylalkene is converted into an intermediate
Reactivity of the ester group attached isoxazoline, benzisoxazole, and isoxazole: a facial preparation of 3-acyl-substituted these heterocycles
作者:Kenichi Murai、Shuji Miyazaki、Hiromichi Fujioka
DOI:10.1016/j.tetlet.2012.05.006
日期:2012.7
A facilepreparation of 3-acyl-substituted isoxazolines, benzisoxazoles, and isoxazoles from the corresponding 3-carboxylate esters is described. The process, involving reaction of the ester derivative of 3-carboxylic acid substituted heterocycles with Grignard or alkynyl lithium reagents, leads to direct generation of the corresponding 3-acyl heterocycle. The presence of α-imino ester moieties in
Synthesis of 4,5-Dihydroisoxazoles by Condensation of Primary Nitro Compounds with Alkenes by Using a Copper/Base Catalytic System
作者:Luca Cecchi、Francesco De Sarlo、Fabrizio Machetti
DOI:10.1002/chem.200800554
日期:2008.9.8
A new procedure for the synthesis of 4.5-dihydroisoxazoles by condensation of primarynitrocompounds with olefins by using a copper/base catalytic system is described. The catalytic effect of copper(II) salts is evidenced by comparison of the reaction rates. Thus, activatednitrocompounds react faster than with organic catalysis by tertiary amines, whereas nitroalkanes, unable to condense with dipolarophiles
1,4-Diazabicyclo[2.2.2]octane (DABCO) as an Efficient Reagent for the Synthesis of Isoxazole Derivatives from Primary Nitro Compounds and Dipolarophiles: The Role of the Base
作者:Luca Cecchi、Francesco De Sarlo、Fabrizio Machetti
DOI:10.1002/ejoc.200600475
日期:2006.11
The dehydration of primary nitro compounds can be performed by bases in the presence of dipolarophiles. The reactivity of several tertiary amines or azaheteroaromatic compounds containing one or two basic centres is shown to be related to the ability of the protonated base to establish H-bonded ion pairs with the adduct that is formed from the nitronate and the dipolarophile in chloroform. Among the
初级硝基化合物的脱水可以在偶极试剂存在下通过碱进行。几种叔胺或含有一个或两个碱性中心的氮杂杂芳族化合物的反应性被证明与质子化碱与氯仿中硝基和亲偶极体形成的加合物建立 H 键离子对的能力有关。在检测的有机碱中,笼状叔二胺 1,4-二氮杂双环 [2.2.2] 辛烷 (DABCO) 的结果最好。该反应适用于活化的硝基化合物和苯基硝基甲烷,与其他方法相比,异恶唑啉衍生物的产率更高。然而,该反应与硝基烷烃不相容。所提出的反应机理是基于氢键离子对的坍塌。
Nitration–Peroxidation of Alkenes: A Selective Approach to β-Peroxyl Nitroalkanes
作者:Yuanjin Chen、Yangyang Ma、Liangkui Li、Hao Jiang、Zhiping Li
DOI:10.1021/acs.orglett.9b00266
日期:2019.3.1
Nitration–peroxidation of alkenes for the synthesis of β-peroxyl nitroalkanes has been developed by using tert-butyl nitrite and tert-butyl hydroperoxide. The method presents a new and selective difunctionalization of alkenes to introduce a nitro group and a peroxyl group across the double bonds of alkenes under mild conditions. A radical reaction pathway is proposed by experimental and theoretical