New Regiospecific Catalytic Approaches to 4,5-Dihydroisoxazoles and 2,5-Dihydroisoxazoles from O-Propargylic Hydroxylamines
作者:David Knight、Anthony Proctor、John Clough
DOI:10.1055/s-0029-1219365
日期:2010.3
Unprotected O-propargylic hydroxylamines undergo generally essentially quantitative cyclisations when exposed briefly to silver nitrate adsorbed onto silica gel to give 4,5-dihydroisoxazoles [2-isoxazolines], while N-protected derivatives give the corresponding 2,5-dihydroisoxazoles [3-isoxazolines] in similarly excellent yields, given that an appropriate functionality on nitrogen is used.
作者:Francesco de Sarlo、Antonio Guarna、Alberto Brandi、Andrea Goti
DOI:10.1016/s0040-4020(01)96763-8
日期:1985.1
The availability of a new synthesis of fulminic acid by hydrolysis of trimcthylsilanecarbonitrile oxide allowed a reinvestigation of the chemistry of the title compound. Thus, cycloadditions to olefinic and acetylenicdipolarophiles are improved with respect to previous results and the oligomerisation is proved to occur via the reactive species hydroxyiminoacetonitrile oxide 7 and hydroxyiminometh
Isomerization of 3-unsubstituted 4,5-dihydroisoxazoles over alumina. A new synthesis of β-hydroxy nitriles
作者:S. S. Mochalov、A. N. Fedotov、E. V. Trofimova、R. A. Gazzaeva、N. S. Zefirov
DOI:10.1134/s1070428016030179
日期:2016.3
3-Unsubstituted 4,5-dihydroisoxazoles obtained by nitrosation of arylcyclopropanes are capable of undergoing efficient isomerization into 3-aryl-3-hydroxypropanenitriles during chromatography on alumina.
The first synthesis of nitro-substituted cyclopropanes and spiropentanes via oxidation of the corresponding amino derivatives
作者:Yuliya A. Volkova、Olga A. Ivanova、Ekaterina M. Budynina、Eugene V. Revunov、Elena B. Averina
DOI:10.1016/j.tetlet.2009.03.165
日期:2009.6
A novel approach to nitro-substituted cyclopropanes and spiropentanes via oxidation of the corresponding amines with dimethyldioxirane is reported. The method is used successfully for the preparation of a series of nitrocyclopropanes as well as for the first synthesis of 1,4-dinitrospiro[2.2]pentane.
Biocatalytic asymmetric ring-opening of dihydroisoxazoles: a cyanide-free route to complementary enantiomers of β-hydroxy nitriles from olefins
作者:Daijun Zheng、Yasuhisa Asano
DOI:10.1039/d0gc01445a
日期:——
the cyanide-free synthesis of chiral nitriles and the Kemp elimination reaction catalyzed by aldoxime dehydratases, we herein report a new application of aldoxime dehydratase in the asymmetric ring-opening of 5-sub-4,5-dihydroisoxazoles to synthesize chiral β-hydroxy nitriles with broad substrate scope, excellent enantioselectivity (up to 99% ee), and good turnover number (up to 11 s−1). Upon simple
通过手性腈的无氰化物合成和醛肟脱水酶催化的坎普消除反应的结合,我们在此报道醛肟脱水酶在5-sub-4,5-二氢异恶唑的不对称开环中合成手性β的新应用-羟基腈,具有广泛的底物范围,出色的对映选择性(高达99%ee)和良好的周转率(高达11 s -1)。简单分离并用碱性试剂处理后,剩余的手性5-sub-4,5-二氢异恶唑可轻松转化为它们相应的β-羟基腈。使用定点诱变,证实了含亚铁血红素的活性位点,并提出了两种可能的去质子化途径。据我们所知,这是第一个用于从一个简单的烯烃一步一步构建手性羟基和腈基的酶促反应,这为合成β-羟基互补对映异构体提供了一种新颖而有用的策略腈。