Organic Reactions Catalyzed by Methylrhenium Trioxide: Dehydration, Amination, and Disproportionation of Alcohols
摘要:
Methylrhenium trioxide (MTO) is the first transition metal complex in trace quantity to catalyze the direct formation of ethers from alcohols. The reactions are independent of the solvents used: benzene, toluene, dichloromethane, chloroform, acetone, and in the alcohols themselves. Aromatic alcohols gave better yields than aliphatic. Reactions between two different alcohols could also be used to prepare unsymmetric ethers, the best yields being obtained when one of the alcohols is aromatic. MTO also catalyzes the dehydration of alcohols to form olefins at room temperature, aromatic alcohols proceeding in better yield. When primary (secondary) amines were used as the limiting reagent, direct amination of alcohols catalyzed by MTO gave good yields of the expected secondary (tertiary) amines at room temperature. Disproportionation of alcohols to alkanes and carbonyl compounds was also observed for aromatic alcohols in the presence of MTO. On the basis of the results of this investigation and a comparison with the interaction between MTO and water, a concerted process and a mechanism involving carbocation intermediates have been suggested.
DOI:
10.1021/jo951613a
作为试剂:
描述:
三乙胺 、 7-氨基去乙酰氧基头孢烷酸 、 三苯基氯甲烷 、 盐酸 在
乙酸乙酯 、 盐酸 、 碳酸氢钠 、 氯化钠 、 Sodium sulfate-III 、 异丙醚 、 oct-3-ene 作用下,
以
N,N-二甲基甲酰胺 、 氯仿 为溶剂,
-20.0~40.0 ℃
、710.99 kPa
条件下,
反应 26.0h,
以A mixture (22.2 g) of 2-carboxy-3-methyl-8-oxo-7-tritylamino-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene (40%) and its oct-3-ene isomer (60%) is obtained in the form of a cream-coloured solid的产率得到2-carboxy-3-methyl-8-oxo-7-tritylamino-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene
Bidentate NHC-Cobalt Catalysts for the Hydrogenation of Hindered Alkenes
作者:Zeyuan Wei、Yujie Wang、Yibiao Li、Raffaella Ferraccioli、Qiang Liu
DOI:10.1021/acs.organomet.0c00498
日期:2020.9.14
Herein, we report a series of easily accessible bidentate N-heterocyclic carbene (NHC) cobalt catalysts, which enable the hydrogenation of hindered alkenes under mild conditions. The four-coordinated bidentate NHC-Co(II) complexes were characterized by X-ray diffraction, elemental analysis, ESI-HRMS, and magnetic moment measurements, revealing a distorted-tetrahedral geometry and a high-spin configuration
POCN Ni(<scp>ii</scp>) pincer complexes: synthesis, characterization and evaluation of catalytic hydrosilylation and hydroboration activities
作者:Kristina A. Gudun、Medet Segizbayev、Assyl Adamov、Philipp N. Plessow、Konstantin A. Lyssenko、Mannix P. Balanay、Andrey Y. Khalimon
DOI:10.1039/c8dt04854a
日期:——
reactions with HBPin, efficient and mild hydroboration of a variety of carbonyl compounds, including highly chemoselective hydroboration of benzaldehyde in the presence of other common potent reductive functional groups, such as alkenes, alkynes, esters, amides, nitriles, nitro compounds and even ketones, and the first example of base metal catalyzed hydroboration of amides, including mild direct hydroborative
一系列亚氨基次膦酸酯POCN钳制Ni(II)配合物(POCN)NiMe和(POCN)NiL n(BX 4)(L = CH 3 CN,n = 0,1; X = F,Ph,C 6 F 5)已开发出用于烯烃,醛和酮的催化氢化硅烷化和羰基化合物的氢硼化反应。(POCN)NiMe和(POCN)Ni(BF 4)与PhSiH 3和HBPin的化学计量反应表明催化反应通过氢化物中间体(POCN)NiH。关于与HBPin的反应,对各种羰基化合物进行了有效而温和的硼氢化,包括在存在其他常见的强还原性官能团(例如烯烃,炔烃,酯,酰胺,腈,硝基化合物和(POCN)NiMe证明了贱金属催化酰胺加氢硼化的第一个实例,包括将伯酰胺和仲酰胺轻度直接硼氢化还原成硼化胺。
Reactivity of bismuth(III) halides towards alcohols. A tentative to mechanistic investigation
作者:El Mehdi Keramane、Bernard Boyer、Jean-Pierre Roque
DOI:10.1016/s0040-4020(01)00013-8
日期:2001.3
bismuth(III) halides (BiX3; X=Cl, Br and I) towards a series of alcohols has been investigated. Three different reactions have been studied, namely: halogenation, dehydration and etherification. The behaviour of these bismuth derivatives was found to depend on the nature of the halide bonded to the bismuth atom. Their reactivities can be interpreted on the basis of the Hard and Soft Acids and Bases
研究了卤化铋(III)(BiX 3; X = Cl,Br和I)对一系列醇的反应性。已经研究了三种不同的反应,即:卤化,脱水和醚化。发现这些铋衍生物的行为取决于结合到铋原子上的卤化物的性质。它们的反应性可以根据硬酸和软酸和碱(HSAB)原理进行解释。提出了一种机制,该机制涉及形成醇与Bi(III)的复合物。
[EN] PROCESS FOR DEHYDROGENATION OF ALKYL-CONTAINING COMPOUNDS USING MOLYBDENUM AND TUNGSTEN NITROSYL COMPLEXES<br/>[FR] PROCÉDÉ POUR LA DÉSHYDROGÉNATION DE COMPOSÉS CONTENANT UN GROUPEMENT ALKYLE À L'AIDE DE COMPLEXES NITROSYLÉS DE MOLYBDÈNE ET DE TUNGSTÈNE
申请人:DOW GLOBAL TECHNOLOGIES LLC
公开号:WO2016112237A1
公开(公告)日:2016-07-14
A process for the dehydrogenation of alkyl-containing compounds comprises reacting an alkyl-containing compound and a Group VI nitrosyl complex characterized as a transition metal complex having the composition Cp'M(NO)(R1)(R2), wherein Cp' is selected from certain substituted and unsubstituted η5-cyclopentadienyl groups; M is W or Mo; and R1 and R2 are independently selected from CH2C(CH3)3; CH2Si(CH3)3; CH2(C6H5); CH3; hydrogen; and η3-allyl; provided that if R1 is hydrogen, R2 is η3-allyl; under conditions such that the alkyl-containing compound is converted to an olefin, and in particular embodiments, a terminal olefin. The dehydrogenation can be carried out using a neat and/or undried alkyl-containing compound and/or may be conducted under air, and does not require a sacrificial olefin to drive the reaction, thereby increasing convenience and decreasing cost in comparison with some other dehydrogenation processes.
Hydroxy- and alkoxycarbonylation reactions constitute important industrial processes in homogeneous catalysis. Nowadays, palladium complexes constitute state-of-the-art catalysts for these transformations. Herein, we report the first efficient platinum-catalysed alkoxycarbonylations of olefins including sterically hindered and functionalized ones. This atom-efficient catalytic transformation provides