通过简单的一锅法沉淀法制备了由少量Pd(0.2 wt%)促进的具有不同Ni / Ce摩尔比的Ce-Ni混合氧化物。如此合成的CeNi X O Y和Pd–CeNi X O Y催化剂分别在不存在碱性添加剂的情况下,在O 2下,通过氧化偶合,直接用于胺和醇的N-烷基化反应。CeNi X O Y催化剂可在100°C的苯胺与苄醇的模型烷基化反应中提供> 99%的亚胺收率。钯促进的Pd–CeNi X O Y在60°C的温和温度下,该催化剂出人意料地显示出提高的亚胺收率(> 99%)。该催化剂显示出良好的可重复使用性,此外,还显示出由多种胺与醇合成亚胺的高性能。Pd物种的存在和Ni / Ce摩尔比对苯胺的转化以及产物的选择性具有协同作用,据信这与苯甲醇氧化为苯甲醇的内在活性的提高有关。苯甲醛。主要采用各种物理化学技术,包括ICP-MS,XRD,N 2吸附-脱附,UV-拉曼光谱,H 2 -TPR,TEM,
Direct oxidativecoupling of alcohols and amines is regarded as an effective and green approach for imine synthesis under mild conditions. In this work, Zn-doped γ-Al2O3 supported Au nanoparticles was demonstrated as highly active and selective heterogeneous catalyst for a series of imine productions with good to excellent yields, from alcohols and amines via direct oxidativecoupling under air atmosphere
醇和胺的直接氧化偶合被认为是在温和条件下合成亚胺的有效且绿色的方法。在这项工作中,锌掺杂的γ-Al 2 ö 3支持的Au纳米颗粒被证明为没有额外的空气气氛下,高活性和选择性的非均相催化剂进行一系列具有良好到优异的产率亚胺制作的,从通过直接氧化偶合醇和胺基础添加剂。研究了各种物理化学技术,包括ICP-MS,XRD,N 2物理吸附,TEM,XPS和CO 2- / NH 3 -TPD。分散良好的Au 0纳米粒子的平均大小约为 在反应性胺的存在下,发现2.9nm对活化醇非常有效。Zn 2+掺杂剂的量和催化剂制备过程中载体的煅烧温度显示出对调节苄醇氧化为苯甲醛的内在活性(即模型反应的速率确定步骤)的关键影响,据报道这是与活性表面氧种类和载体的酸碱性有关。在400°C下煅烧的0.4%Au / Zn 0.02 Al 2 O 3催化剂表现出最高的TOF(39.1 h -1)在60°C的条件下,在所有已报道的金基催化剂中,对亚苄基苯胺的收率均>
Efficient Imine Formation by Oxidative Coupling at Low Temperature Catalyzed by High‐Surface‐Area Mesoporous CeO
<sub>2</sub>
with Exceptional Redox Property
the structural and redox properties. The hsmCeO2 calcined at 400 °C shows the highest specific surfacearea (158 m2 g−1), the highest fraction of surface coordinatively unsaturated Ce3+ ions (18.2 %), and the highest concentration of reactive oxygen vacancies (2.4×1015 spins g−1). In the model reaction of oxidative coupling of benzyl alcohol and aniline, such an exceptional redox property of the hsmCeO2
高表面积介孔CeO 2(hsm CeO 2)是通过一种容易的有机模板诱导的均匀沉淀过程制备的,在低温下空气中没有伯醇和胺的碱存在下,在亚胺合成中显示出优异的催化活性。 。为了比较,还研究了不同热处理后的普通CeO 2和hsm CeO 2。XRD,N 2物理吸附,UV-拉曼光谱,H 2程序升温还原,O 2程序升温脱附,EPR光谱和X射线光电子能谱被用来揭示结构和氧化还原特性。这在400°C下煅烧的hsm CeO 2表现出最高的比表面积(158 m 2 g -1),最高的表面配位不饱和Ce 3+离子份额(18.2%)和最高的活性氧空位浓度(2.4× 10 15 旋转g -1)。在苯甲醇和苯胺的氧化偶合模型反应中,hsm CeO 2催化剂的这种出色的氧化还原性质可以促进苄叉基苯胺的形成(2.75和5.55 mmol h -1基于在无碱添加剂的空气中分别在60和80°C下> 99%的收率。它也
Diethylsilane as a Powerful Reagent in Au Nanoparticle-Catalyzed Reductive Transformations
Diethylsilane exhibits remarkable reactivity relative to typical hydrosilanes in the reduction of carbonyl compounds, imines, and amides catalyzed by Au nanoparticles.
Organic Reactions Catalyzed by Methylrhenium Trioxide: Reactions of Ethyl Diazoacetate and Organic Azides
作者:Zuolin Zhu、James H. Espenson
DOI:10.1021/ja954039t
日期:1996.1.1
para position of phenols favors the formation of α-phenoxy ethyl acetates. The use of EDA to form α-thio ethyl acetates and N-substituted glycine ethyl esters, on the other hand, is hardly affected by the size or structure of the parent thiol or amine, with all of these reactions proceeding in high yield. MTO-catalyzed cycloaddition reactions occur between EDA and aromatic imines, olefins, and carbonyl
Photoredox Radical/Polar Crossover Enables Construction of Saturated Nitrogen Heterocycles
作者:Loïc R. E. Pantaine、John A. Milligan、Jennifer K. Matsui、Christopher B. Kelly、Gary A. Molander
DOI:10.1021/acs.orglett.9b00602
日期:2019.4.5
Photoredox-mediated radical/polar crossover (RPC) processes offer new avenues for the synthesis of cyclic molecules. This process has been realized for the construction of medium-sized saturated nitrogen heterocycles. Photocatalytically generated alkylradicals possessing pendant leaving groups engage imines in C–C bond formation, and subsequent reduction of the intermediate nitrogen-centered radical triggers