Surface-Mediated Reactions. 9. Selective Oxidation of Primary and Secondary Amines to Hydroxylamines<sup>1</sup>
作者:John D. Fields、Paul J. Kropp
DOI:10.1021/jo0002083
日期:2000.9.1
OXONE over silica gel or, in some cases, alumina has been found to oxidize the primary and secondaryamines 3 selectively to the corresponding hydroxylamines 4, in either the presence or absence of a solvent. Treatment of Boc-protected L-lysine (6) under the latter conditions afforded hydroxylamine 7 in excellent yield. The trialkylamine 1a and pyridine (1b), in which selectivity is not an issue, were
Selective reductive coupling of nitro aliphatic compounds with aldehydes in hydrogen using gold catalyst
作者:Larisha Cisneros、Pedro Serna、Avelino Corma
DOI:10.1016/s1872-2067(16)62493-2
日期:2016.10
Nitrones were synthesized in good yields directly from nitro aliphatic compounds, aldehydes, and H 2 using highly dispersed gold nanoparticles on titania. The high selectivity for nitrone synthesis contrasts with the platinum supported on carbon and corresponds to an increase from roughly 50% to 90%. The catalytic performance is tuned by precise control of the struc-ture of the active sites, the characteristics
使用高度分散的金纳米粒子在二氧化钛上直接从硝基脂肪族化合物、醛和 H 2 合成了高产率的硝酮。硝酮合成的高选择性与碳负载铂形成对比,对应于从大约 50% 增加到 90%。通过精确控制活性位点的结构、载体的特性和反应条件来调节催化性能。
Epoxidation of Alkenes with Hydrogen Peroxide Catalyzed by Selenium-Containing Dinuclear Peroxotungstate and Kinetic, Spectroscopic, and Theoretical Investigation of the Mechanism
210 h−1 for the epoxidation of cyclohexene catalyzed by I with H2O2. The catalyst was easily recovered and reused with maintenance of the catalytic performance. The SeO42− ligand in I played an important role in controlling the Lewis acidity of the peroxotungstates, which significantly affects their electrophilic oxygen-transfer reactivity. Several kinetic and spectroscopic results showed that the present
具有SeO 4 2-配体(TBA)2 [SeO 4 WO(O 2)2 } 2 ](I ; TBA = [(n -C 4 H 9)4 N] +)的双核过氧钨酸盐可以起作用作为有效的均相催化剂,以H 2 O 2为唯一氧化剂,可选择性氧化各种有机物质,例如烯烃,醇和胺。I与H 2催化环己烯环氧化的周转频率(TOF)高达210 h -1O 2。催化剂易于回收并在保持催化性能的情况下重复使用。SEO的4 2-配体在我在控制peroxotungstates,其中显著影响它们的电氧气转移反应的路易斯酸性中发挥了重要的作用。几个动力学和光谱结果表明,本催化环氧化包含以下两个步骤:(i)形成的随后的过氧物种[缝的米ö Ñ ] ø - (II ;米= 1和2)通过反应我与的烯烃和(ii)再生我通过反应II具有H 2 O 2。在稳态周转条件下,化合物I是优势种。催化环氧化的反应速率显示出对烯烃和I的浓度的一阶依赖性,以及对H
Strain-Release Driven Cycloadditions for Rapid Construction of Functionalized Pyridines and Amino Alcohols
describes the development of a new variant of stereoselective strain-release driven reactions (formal homo [3 + 2] dipolarcycloadditions) which utilize housane (1) to construct functionalized amino alcohols and pyridine-substituted cyclopentanes in two to three steps from simple and easily available building blocks (nitrones and pyridine N-oxides respectively).
Oxidation of Primary Amines to Oximes with Molecular Oxygen using 1,1-Diphenyl-2-picrylhydrazyl and WO<sub>3</sub>/Al<sub>2</sub>O<sub>3</sub> as Catalysts
water as a side product. Various alicyclic amines and aliphatic amines can be converted to their corresponding oximes in excellent yields. It is noteworthy that the oxidative transformation of primaryamines proceeds chemoselectively in the presence of other functional groups. The key step of the present oxidation is a fast electron transfer from the primaryamine to DPPH followed by proton transfer to
在催化剂1,1-二苯基-存在下,用分子氮稀释的分子氧(O 2 / N 2 = 7/93 v / v,5 MPa)下,伯胺向其相应的肟的氧化转化高效进行。2-吡啶甲基肼基(DPPH)和氧化古铜粉/氧化铝(WO 3 / Al 2 O 3)。该方法对环境无害,因为该反应仅需要分子氧作为末端氧化剂,并产生水作为副产物。各种脂环族胺和脂族胺可以优良的产率转化为它们相应的肟。值得注意的是,伯胺的氧化转化在其他官能团存在下化学选择性地进行。本氧化的关键步骤是将电子从伯胺快速转移至DPPH,然后进行质子转移,以生成α-氨基烷基自由基中间体,该中间体与分子氧和氢的夺取反应生成α-氨基烷基氢过氧化物。过氧化物与WO 3 / Al 2 O 3的后续反应产生肟。仲胺的需氧氧化产生相应的硝酮。环己胺的有氧氧化转化为环己酮肟作为工业生产ε-己内酰胺(尼龙6的原料)的方法很重要。