Regiochemical control of the ring opening of 1,2-epoxides by means of chelating processes. 8. Synthesis and ring opening reactions of cis- and trans- oxides derived from 3-benzyloxycyclohexene and 2-benzyloxy-5,6-dihydro-2H-pyran
The regiochemical outcome of the ring opening of 1,2-epoxides bearing polar remote functionalization through chelation processes assisted by metal ions, was verified in cyclic oxirane systems having the polar functionality in an allylic position to the oxirane ring. The diastereoisomeric cis/trans epoxide pairs 5,6 and 7,8 derivedfrom 3-benzyloxycyclohexene, and 2-benzyloxy-5,6-dihydro-2H-pyran, respectively
在具有在环氧乙烷环的烯丙基位置上具有极性官能团的环状环氧乙烷体系中,证实了通过金属离子辅助的螯合过程通过极性远程官能化而带有极性远程官能化的1,2-环氧化物的开环的区域化学结果。非对映体顺式/反式环氧化物对5,6和7,8由3- benzyloxycyclohexene衍生,和2-苄氧基- 5,6-二氢-2 H ^ -吡喃,分别制备和几个其开口的反应进行了研究。观察到的区域选择性在很大程度上取决于反应条件(标准条件或金属辅助条件),并且有趣地取决于所用亲核试剂的性质。
Oxygen transfer reactions from an Oxaziridinium tetrafluoroborate salt to Olefins
作者:Xavier Lusinchi、Gilles Hanquet
DOI:10.1016/s0040-4020(97)00890-9
日期:1997.10
Oxaziridinium efficiently epoxidises olefins. It reacts as an electrophilic reagent and does not transfer its oxygen to deactivated double-bonds or carbonyl functions. Epoxidation of cyclic allylic acetates shows a remarkable diastereoselectivity leading to the syn isomer. We propose that the epoxidation reaction proceeds through a one-step process.
and green catalytic deoxygenation of epoxides to alkenes using goldnanoparticles (NPs) supported on hydrotalcite [HT: Mg6Al2CO3(OH)16] (Au/HT) with alcohols, CO/H2O or H2 as the reducing reagent. Various epoxides were selectively converted to the corresponding alkenes. Among the novel metal NPs on HT, Au/HT was found to exhibit outstanding catalytic activity for the deoxygenation reaction. Moreover
Manganese(II)/Picolinic Acid Catalyst System for Epoxidation of Olefins
作者:Ross A. Moretti、J. Du Bois、T. Daniel P. Stack
DOI:10.1021/acs.orglett.6b00518
日期:2016.6.3
An in situ generated catalyst system based on Mn(CF3SO3)2, picolinic acid, and peracetic acid converts an extensive scope of olefins to their epoxides at 0 °C in <5 min, with remarkable oxidant efficiency and no evidence of radical behavior. Competition experiments indicate an electrophilic active oxidant, proposed to be a high-valent Mn = O species. Ligand exploration suggests a general ligand sphere
基于Mn(CF 3 SO 3)2,吡啶甲酸和过氧乙酸的原位生成的催化剂体系在0°C下于<5分钟内将大量烯烃转化为环氧化物,具有显着的氧化效率并且没有自由基的迹象行为。竞争实验表明,一种亲电子活性氧化剂被认为是高价Mn = O物种。配体探索表明,一般的配体球基序有助于有效氧化。该方法以其简单性和使用廉价试剂来快速获得高附加值产品而得到强调。
g-C<sub>3</sub>N<sub>4</sub>/metal halide perovskite composites as photocatalysts for singlet oxygen generation processes for the preparation of various oxidized synthons
g-C3N4/metal halide perovskite composites were prepared and used for the first time as photocatalysts for in situ 1O2 generation to perform hetero Diels–Alder, ene and oxidation reactions with suitable dienes and alkenes. The standardized methodology was made applicable to a variety of olefinic substrates. The scope of the method is finely illustrated and the reactions afforded desymmetrized hydroxy-ketone
制备了gC 3 N 4 /金属卤化物钙钛矿复合材料,并首次用作原位 1 O 2的光催化剂,以进行杂Diels-Alder,烯烃和与合适的二烯和烯烃的氧化反应。使标准化的方法学适用于各种烯烃底物。很好地说明了该方法的范围,并且反应得到了不对称的羟基酮衍生物,不饱和酮和环氧化物。还观察到一些局限性,特别是在烯烃氧化的情况下,并且在这项工作中观察到较差的化学选择性,这是基于MHP的复合材料在原位 1 O 2中的首次应用代。实验协议可以用作进一步扩展MHP在有机反应中的知识和适用性的平台,因为钙钛矿提供了丰富的调节策略,可用于提高反应产率和选择性。