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羰基化合物的还原偶联是形成C-C键的重要方法.早在本世纪初,有人就研究了醛酮的电解还原偶联反应,但所用的电极为Hg、Pd、Pt、Cd等,且电解过程有诸多不便.八十年代中期出现了一种以消耗性金属Mg、Al、Zn为阳极,石墨等为阴极的有机电极合成方法[1]. 相似文献
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研究了通过萘锂还原法制得的活性镁与环戊二烯原位合成环戊二烯基镁(Cp~2Mg)的方法。Cp~2Mg的存在是由它与醛酮反应生成富烯得到证实。此法产率高, 方法简单, 条件温和。 相似文献
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A convenient and efficient method for the hydrogenative cleavage of azo compounds to corresponding amine (s) using chitosan-supported formate as hydrogen donor in conjunction with low-cost magnesium powder is reported. This method was found to be highly facile with selectivity over several other functional groups, such as halogen, alkene, nitrile, carbonyl, ether, amide, methoxy, and hydroxyl groups. Furthermore, this mild, exceedingly efficient, and highly chemoselective method simplifies the handling and separation procedures. 相似文献
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( + ) Altholactone ,amemberofnewtypeofcyto toxicnaturalstyryllactone ,hasbeenknowntopossessantitumoractivityagainstmurineP338leukemiaandshowlethalitytobrineshrimp .1Recently ,areportonitsstruc ture activityrelationship2 andpapersontheapplicationofnewsyntheticme… 相似文献
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Julia Intemann Dr. Jan Spielmann Dr. Peter Sirsch Prof. Dr. Sjoerd Harder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(26):8478-8489
A new tetranuclear magnesium hydride cluster, [{ NN ‐(MgH)2}2], which was based on a N? N‐coupled bis‐β‐diketiminate ligand ( NN 2?), was obtained from the reaction of [{ NN ‐(MgnBu)2}2] with PhSiH3. Its crystal structure reveals an almost‐tetrahedral arrangement of Mg atoms and two different sets of hydride ions, which give rise to a coupling in the NMR spectrum (J=8.5 Hz). To shed light on the relationship between the cluster size and H2 release, the thermal decomposition of [{ NN ‐(MgH)2}2] and two closely related systems that were based on similar ligands, that is, an octanuclear magnesium hydride cluster and a dimeric magnesium hydride species, have been investigated in detail. A lowering of the H2‐desorption temperature with decreasing cluster size is observed, in line with previously reported theoretical predictions on (MgH2)n model systems. Deuterium‐labeling studies further demonstrate that the released H2 solely originates from the oxidative coupling of two hydride ligands and not from other hydrogen sources, such as the β‐diketiminate ligands. Analysis of the DFT‐computed electron density in [{ NN ‐(MgH)2}2] reveals a counterintuitive interaction between two formally closed‐shell H? ligands that are separated by 3.106 Å. This weak interaction could play an important role in H2 desorption. Although the molecular product after H2 release could not be characterized experimentally, DFT calculations on the proposed decomposition product, that is, the low‐valence tetranuclear Mg(I) cluster [( NN ‐Mg2)2], predict a structure with two almost‐parallel, localized Mg? Mg bonds. As in a previously reported β‐diketiminate MgI dimer, the Mg? Mg bond is not characterized by a bond critical point, but instead displays a local maximum of electron density midway between the atoms, that is, a non‐nuclear attractor (NNA). Interestingly, both of the NNAs in [( NN ‐Mg2)2] are connected through a bond path that suggests that there is bonding between all four MgI atoms. 相似文献
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Dr. Andreas Stasch 《Angewandte Chemie (International ed. in English)》2014,53(38):10200-10203
The synthesis of dimeric magnesium(I) compounds of the general type RMgMgR (R=monoanionic substituent) is still a challenging synthetic task and limited to few examples with sterically demanding ligands with delocalized CN‐frameworks that all have been accessed by Na or K metal reduction of magnesium(II) halide precursors. Here we report on the synthesis of a novel diiminophosphinato magnesium(I) compound that has been synthesized by a facile redox reaction using a known magnesium(I) complex. The synthetic strategy may be applicable to other ligand systems and can help expand the class of low oxidation state magnesium complexes even if reductions with Na or K are unsuccessful. The new dimeric magnesium(I) complex has been structurally characterized and undergoes a C? C coupling reaction with tert‐butylisocyanate. 相似文献
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Chong Yan Rui Xu Jin‐Lei Qin Hong Yuan Ye Xiao Lei Xu Jia‐Qi Huang 《Angewandte Chemie (International ed. in English)》2019,58(43):15164-15164
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Structure and Reaction Chemistry of Magnesium Organocuprates Derived from Magnesiacyclopentadienes and Copper(I) Salts 下载免费PDF全文
Liang Liu Dr. Junnian Wei Yue Chi Prof. Dr. Wen‐Xiong Zhang Prof. Dr. Zhenfeng Xi 《Angewandte Chemie (International ed. in English)》2016,55(47):14762-14765
The chemistry of magnesium organocuprates, including their synthesis, structures, and reactions, remains underexplored. In this work, by taking advantage of the high reactivity and ready availability of magnesiacyclopentadienes, a series of magnesiacyclopentadiene‐based organocuprates were synthesized and structurally characterized. A variety of CuX salts (X=Cl, Br, I, or alkynyl) were successfully applied to react with magnesiacyclopentadienes. Besides CuX salts, AgX salts (X=Cl, alkynyl) also undergwent the above reaction to afford the corresponding magnesium organoargentates. Single‐crystal X‐ray structural analysis and DFT calculations of these butadienyl magnesium organocuprates revealed unique structural characteristics and bonding modes. These results are also very useful to understand the transmetalation process, since the product can be viewed as the resting‐state intermediate of a transmetalation reaction between organomagnesium compounds and coinage‐metal salts. Preliminary information on the reaction chemistry of these magnesium organocuprates is provided by their reactions with allyl bromide, benzoyl chloride, and CO2. 相似文献
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简要分析各种储氢材料和技术的基础上,重点介绍了高比表面积活性炭的制备方法,目前最常用的活化方法是以氢氧化钾为活化剂的化学活化法;并总结了近年来前人在高比表面积活性炭储氢方面的研究结果,同时简要分析了高比表面积活性炭储氢机理方面的研究进展. 相似文献