A metal‐free deoxygenation and reductive disilylation of nitroarenes was achieved using N,N′‐bis(trimethylsilyl)‐4,4′‐bipyridinylidene (1) under mild and neutral reaction conditions, and a broad functional group tolerance was possible in this reaction. Mono‐deoxygenation, giving a synthetically valuable N,O‐bis(trimethylsilyl)phenylhydroxylamine (7 a) as a readily available and safe phenylnitrene source
使用N,N'-双(三甲基甲硅烷基)-4,4'-联吡啶亚烷基(1)在温和和中性的反应条件下实现了硝基芳烃的无金属脱氧和还原二甲硅烷基化反应,并且该反应可能具有广泛的官能团耐受性。单脱氧可得到合成上有价值的N,O-双(三甲基甲硅烷基)苯羟胺(7 a),是一种容易获得且安全的硝基苯来源的苯基亚硝酸,双脱氧可得到N,N-双(三甲基硅烷基)苯胺8。改变1的量很容易控制反应温度以及加入二苯并噻吩(DBTP)。2-芳基硝基苯与1的反应通过N,O-双(三甲基甲硅烷基)苯基羟胺7的热解衍生的原位生成的亚苯基硝基苯胺生成相应的咔唑14,随后将其插入分子内CH。此外,分子内的N-N偶联反应将2,2'-二硝基联苯衍生物还原1,得到相应的苯并[ c ]喹啉。
1,4-Bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadienes as Strong Salt-Free Reductants for Generating Low-Valent Early Transition Metals with Electron-Donating Ligands
reduction of Cp2TiCl2, for which compounds 2a and 4 gave the corresponding one-electron reduced products, pyrazine-bridged and 4,4'-bipyridyl-bridged dimeric Ti(III) complexes 5 and 6, and compounds 2b and 2c afforded the same double chloride-bridged dimeric Ti(III) complex, [Cp2Ti]2(μ-Cl)2 (7), though 1a and 1b could not reduce Cp2TiCl2. Application of the organosiliconcompounds as reducing agents for catalytic
Reductive Silylation Using a Bis‐silylated Diaza‐2,5‐cyclohexadiene
作者:Daniel M. Beagan、I. J. Huerfano、Alexander V. Polezhaev、Kenneth G. Caulton
DOI:10.1002/chem.201900879
日期:2019.6.18
1,4‐Bis(trimethylsilyl)‐1,4‐diaza‐2,5‐cyclohexadiene, 1, was tested as a reagent for the reductive silylation of various unsaturated functionalities, including N‐heterocycles, quinones, and other redox‐active moieties in addition to deoxygenation of main group oxides. Whereas most reactions tested are thermodynamically favorable, based on DFT calculations, a few do not occur, perhaps giving limited
Insertion von CO2, COS and CS2 in die NSi-Bindung des extrem elektronenreichen 1,4-Bis(trimethylsilyl) -1,4-dihydropyrazins und Bildung eines neuen poly(N,S-) heterocyclischen Systems durch mehrfache Cycloaddition
of COS could be added. Carbon disulphide reacts rapidly with 1 under partial oxidative desilylation as evident from the formation of pyrazine; in addition to some insertion, a novel polyheterocyclic system 4 is formed as the main product. The crystallographically characterized red 5r,l0c;6t,9t-diepiazano-thiocino[4,5-b]pyrazine-8-thione derivative 4 is formed by cycloaddition between CS2 and two equivalents
1,4-双(三甲基甲硅烷基)-1,4-二氢吡嗪(1)是一种非常富电子的N-甲硅烷基-烯胺,在平面六元环中具有八个共轭π电子,相对于杂多烯X具有不同的反应性CMYY MYO,S)。将二氧化碳缓慢地插入一个NSi键中,从而得到富电子的O-硅烷基氨基甲酸酯官能团。仅在CO 2压力下才会显着插入第二个NSi键。所有插入反应产物的1 H NMR光谱显示,强烈依赖溶剂的化学位移和NC(X)键周围的受限旋转。羰基硫与1的反应比CO 2更快为了得到结构上表征的O-甲硅烷基硫代氨基甲酸酯衍生物,仅可以添加一分子的COS。从吡嗪的形成可以明显看出,二硫化碳在部分氧化甲硅烷基化反应中与1快速反应。除了插入之外,还形成了新颖的多杂环系统4作为主要产品。通过CS 2与两个当量的1之间的环加成反应,形成晶体学上红色的5 r,10 c ; 6 t,9 t-二叠氮杂-硫代奇诺[4,5-b]吡嗪-8-硫酮衍生物
Probing Hydrogen Atom Transfer at a Phosphorus(V) Oxide Bond Using a “Bulky Hydrogen Atom” Surrogate: Analogies to PCET
作者:Jiaxiang Chu、Timothy G. Carroll、Guang Wu、Joshua Telser、Roman Dobrovetsky、Gabriel Ménard
DOI:10.1021/jacs.8b09063
日期:2018.11.14
(a "bulky hydrogen atom" surrogate) donor, 1,4-bis(trimethylsilyl)pyrazine. While the former reaction led to product decomposition, the latter resulted in the isolation of the reduced, silylated complexes (Ph2N)3V-N═P(OSiMe3)Ar2 (3a/b). Detailed analyses of possible reaction pathways, involving the isolation and full characterization of potential stepwise square-scheme intermediates, as well as the
最近的计算研究表明,商业磷酸钒氧化物 (VPO) 催化剂中的磷酸盐载体可能通过一种类似于质子耦合电子转移 (PCET) 的还原耦合氧活化 (ROA) 机制在引发丁烷 CH 键活化方面发挥关键作用。 ); 然而,没有实验证据支持这种机制。在此,我们提出了分子模型化合物,(Ph2N)3V=NP(O)Ar2 (Ar = C6F5 (2a), Ph (2b)),它们对弱 H 原子供体和 Me3Si•(一种“大体积氢原子”替代物)供体,1,4-双(三甲基甲硅烷基)吡嗪。虽然前一个反应导致产物分解,但后者导致分离出还原的硅烷化配合物 (Ph2N)3V-N=P(OSiMe3)Ar2 (3a/b)。可能的反应途径的详细分析,描述了潜在逐步平方方案中间体的分离和完整表征,以及最小实验和计算得出的热化学值的确定。我们发现逐步电子转移 (ET) + 甲硅烷基转移 (ST) 或协调的 EST 机制最有可能。这项研究提供了第一个支持