苄基醚选择性间接电氧化的研究

以Mn(Ⅲ) / Mn(Ⅱ)为 间接氧化还原体系研究苄基醚的氧化. 实验结果表明该体系能高产率选择性地氧化苄基醚为 苯甲醛和相应的醇. 阳极液中Mn(Ⅱ)可以循环使用.     

茴香醛的直接电氧化合成研究

应用循环伏安和恒电位电解法研究了茴香醚在铂电极上直接电氧化行为.考查扫描速率、反应底物浓度、支持电解质和溶剂对该电氧化行为的影响.结果表明,茴香醚在铂电极上的氧化过程是不可逆的.在硫酸/丙酮溶液中,其响应峰电流最高,反应受扩散控制.经GC-MS检测,主要氧化产物为茴香醛,选择性为66.5%.     

NH4Cl.CrO3对烯丙基醚和苄基醚的选择性氧化成酯的研究

本文报道了NH4Cl.CrO3(简称ACC)在无溶剂反应条件下, 以较好的产率, 将烯丙基醚或苄基醚选择性地氧化成相应的酯。     

Au(I)/手性双功能叔胺催化实现的一锅法串联成烯/不对称环化反应构建螺环季碳氧化吲哚

研究报道了Au（I）/手性叔胺串联催化实现的一锅法不对称反应,实现从重氮氧化吲哚和氟代烯醇硅醚出发构建螺环季碳氧化吲哚.反应的第一步是3.0 mol% IPrAuBF₄催化的重氮氧化吲哚与单氟烯醇硅醚的交叉偶联反应,现场产生N-Ac保护的3-烯基氧化吲哚在手性叔胺-四方酸C1的催化下与N-Ts邻氨基查尔酮再发生不对称Michael/Michael反应,以中等到良好的产率以及对映选择性,>20：1的非对映选择性得到螺环季碳氧化吲哚.反应的关键一步是Au（I）催化的给体-受体类重氮化合物与三取代单氟烯醇硅醚的成烯化反应,高效构建三取代烯烃.     

锰氮掺杂的碳材料催化苄基醚氧化生成酯（英文）

报道了一种在无溶剂条件下可回收的锰氮掺杂的碳材料催化叔丁基过氧化氢氧化苄基醚生成酯的催化氧化体系.该催化氧化体系具有好的官能团耐受性、优异的化学选择性,而且该催化氧化体系可以放大.     

NH_4C1·CrO_3对烯丙基醚和苄基醚的选择性氧化成酯的研究

本文报道了NH_4Cl·CrO_3(简称ACC)在无溶剂反应条件下,以较好的产率,将烯丙基醚或苄基醚选择性地氧化成相应的酯。     

微反应器控制的化学反应的选择性

研究利用分子筛、Nafion薄膜、低密度聚乙烯薄膜和囊泡作为微反应器控制有机光化学反应的方向,提高反应的选择性和可能性.在NaY沸石或低密度聚乙烯薄膜中,带有长烷基链或醚链的二芳基化合物光二聚只生成分子内的加成产物,而不生成分子间的加成产物,从而在底物浓度很大的情况下,高选择性地合成了大环化合物.通过控制底物和敏化剂分子在ZSM-5沸石、Nafion薄膜和囊泡中的分布高选择性地控制烯烃光敏氧化反应的方向,单一地生成单重态氧的氧化产物或超氧负离子的氧化产物.利用Nafion薄膜作为介质进行光诱导电子转移,得到超长寿命的电荷分离态.     

Ni(0)催化炔醛偶联反应中配体作用的理论研究

本文运用密度泛函理论(DFT)计算,研究了Ni(0)催化炔烃与醛分子间还原偶联反应的机理,确定了该反应最优反应路径是氧化环化、转金属以及还原消除.计算结果表明,无论使用IMes还是SIPr作为配体,反应的区域选择性都由氧化环化步控制;而硅烷的转金属化是整个反应的决速步.这不同于以往对Ni(0)催化炔醛还原偶联反应的理论研究.理论计算表明,当使用IMes作为配体时,主要产物为2-甲基-3-苯基烯丙基硅醚;当使用SIPr作为配体时,主产物则是3-甲基-2-苯基烯丙基硅醚.无论从主产物还是区域选择性,本文的计算结果都与实验报道一致.本文使用反应路径形变-结合能模型研究了IMes作为配体时的区域选择性.结果表明,形成主产物时具有较低的形变能.也就是说,过渡态中炔烃部分与苯基折叠程度较小,共轭程度更大,因此主产物为2-甲基-3-苯基烯丙基硅醚.本课题组还使用2D投影图模型研究了空间效应对不同配体的影响.结果表明,当使用IMes配体时,由于配体体积较小,可以容纳苯基在其周围,从而减小了炔烃上的苯基与醛上苯基的排斥;而使用大位阻的SIPr作为配体时,配体与炔烃上的苯基排斥很大,从而不利于2-甲基-3-苯基烯丙基硅醚的生成.     

氯化铵三氧化铬在干反应中对苄醚的选择性氧化

本文报道氯化铵三氧化铬(ACC)是具有高选择性的氧化剂, 在无溶剂的干反应中, 可以把苄醚氧化成相应的苯甲酸酯, 且顶点满意的产率.     

对位取代苯基烯丙基醚的烷基化反应

烯丙基醚是一个重要的β-羰基化合物的合成等价物,已有许多应用,它的应用和反应的区域选择性有密切关系.最近,Werstiuk 曾对烯丙基化合物的反应及其在合成上的应用作了综述,并讨论了立体因素对烯丙基化合物反应区域选择性的影响.Evans 等研究了烯丙基烷基醚阴离子和亲电试剂反应中位阻和区域选择性的关系.当亲电试剂是卤代烷时,烯丙基醚中烷基体积增大,γ位烷基化的比例也增大;而亲电试剂为羰     

Molecular Diversity of Tonghaosu Analogues, Selective Oxidation of the exo-Cyclic Double Bond of Spiroacetal Enol Ethers and Diasteroselective Synthesis of Spiro-Pyranone

Two methods including NBS/AgNO₃ system and MCPBA oxidation have been developed for the selective oxidations of the exo‐cyclic double bond of spiroacetal enol ethers 2 with multi reactive sites into spiro‐pyanones 3 and 4 . In addition, possible mechanisms for these conversions are proposed.     

Selective oxidation of ethylbenzene by dioxygen in the presence of complexes of nickel and cobalt with macrocyclic polyethers

The oxidation of alkylarenes by dioxygen in the presence of complexes of nickel and cobalt with macrocyclic ethers 18-crown-6 and 15-crown-5 was studied. The conditions for selective catalytic oxidation of ethylbenzene to α-phenylethyl hydroperoxide were determined. The kinetics of the accumulation of all oxidation products was studied. The order of the formation of the products at different stages of chain oxidation was determined. The activity of the complexes at the elementary stages of the chain oxidation of ethylbenzene is discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 689–693, April. 1997.     

Metal‐Free 2,2,6,6‐Tetramethylpiperidin‐1‐yloxy Radical (TEMPO) Catalyzed Aerobic Oxidation of Hydroxylamines and Alkoxyamines to Oximes and Oxime Ethers

TEMPO‐Mediated oxidation of hydroxylamines (=hydroxyamines) and alkoxyamines to the corresponding oxime derivatives is reported (TEMPO=2,2,6,6‐tetramethylpiperidin‐1‐yloxy radical; Scheme 2). These environmentally benign oxidations proceed in good to excellent yields (Table 1). For alkoxyamines, oxidation to the corresponding oxime ethers can be performed by using dioxygen as a terminal oxidant in the presence of 5–10 mol‐% of TEMPO or 4‐substituted derivatives thereof as a catalyst (Scheme 3 and Table 2). Importantly, benzyl bromides can directly be transformed to oxime ethers via in situ alkoxyamine formation by a nucleophilic substitution followed by TEMPO‐mediated oxidation (Scheme 4 and Table 3).     

Palladium-catalyzed oxidation of vinyl ether to acetate with hydrogen peroxide

The selective hydrogen peroxide oxidation of vinyl ethers to give acetates was developed using triphenylphosphine palladium and triethyl amine catalysts under mild reaction conditions.     

Gas chromatography and mass spectrometry identification of cyclic ethers formed from reference fuels combustion

Summary The major cyclic ethers formed in the cool flame oxidation of reference fuels (normal heptane, isooctane, and normal decane) have been identified by gas chromatography-mass spectrometry. The spectra obtained by electronic ionization are presented. Since these ethers are not available commercially and their mass spectra are missing from standard mass spectrometry libraries the present mass spectra could be used as references in future work.     

Theoretical Study on the Dark Oxidation Reaction Mechanism of Ethers

1 INTRODUCTION Ethers are a kind of organic compounds that are easily oxidized under the conditions of lacking light and any additional excitement. According to dif- ferent mechanisms, the oxidation reactions could be classified into two types: photooxidation reaction and dark oxidation reaction. The former is the reaction with excited state oxygen molecule (singlet state), while the latter is the reaction with ground state oxygen molecule (triple state) without illuminance or any exciter…     

芳醚的催化氧化反应

以取代芳醚为原料,碘苯醋酸酯为氧化剂,二氯甲烷为溶剂,在醋酸铑催化下合成了一系列醌类化合物,其结构经1H NMR,13C NMR和HR-MS确证。     

Efficient and Practical Synthesis of Dissymmetrical Ethers of 4-Nitrocatechol

An efficient and practical synthesis of dissymmetrical ethers of 4-nitrocatechol from 5-nitrosalicyladehyde and 2-hydroxy-5-nitroacetophenone via Baeyer–Villiger oxidation is described. These dissymmetrical ethers are useful in the synthesis of various coccidiostats and other important pharmaceutical intermediates.     

(NO3)3CeBrO3: Solvent‐Free Oxidation of Alcohols and Deprotection and Oxidative Deprotection of Trimethylsilyl Ethers

Trinitratocerium(IV) bromate (TNCB) can be used as an efficient reagent for oxidation of alcohols and deprotection and oxidative deprotection of trimethylsilyl ethers under solvent‐free conditions.