Ionic Ga-Complexes of Alkylidene- and Arylmethylidenemalonates and Their Reactions with Acetylenes: An In-Depth Look into the Mechanism of the Occurring Gallium Chemistry
作者:Roman A. Novikov、Dmitry A. Denisov、Konstantin V. Potapov、Yaroslav V. Tkachev、Evgeny V. Shulishov、Yury V. Tomilov
DOI:10.1021/jacs.8b08913
日期:2018.10.31
formation of polyfunctional vinyl halides with high E-selectivity. The mechanism has been studied experimentally in fine detail. Application of specially optimized 71GaNMRspectroscopy makes it possible to take an in-depth look into the gallium chemistry in a new light. In particular, the key participation of GaHal4- anions in the occurring transformations has been established.
在取代亚甲基丙二酸酯的化学中提出了一种新的合成概念,可以将其用作 1,2-两性离子合成子。该策略是从具有严格 3/4 组成的亚甲基丙二酸酯和 GaHal3 生成液态离子 Ga 络合物,然后将它们用于进一步合成。已经合成并详细研究了许多具有不同金属卤化物的配合物。镓在所有金属中的独特性质已经得到证明和解释。在发现的一类新的亚甲基丙二酸镓配合物的基础上,已经阐述了许多与乙炔的新反应,这些反应在亚甲基丙二酸的常规化学中是未知的。主要展示的过程是对涉及卤化物阴离子的三键进行三组分加成,导致形成具有高 E 选择性的多官能卤乙烯。已经通过实验详细地研究了该机制。特别优化的 71Ga 核磁共振光谱的应用使得以新的视角深入研究镓化学成为可能。特别是,GaHal4-阴离子在发生的转变中的关键参与已经确立。
A BF3·OEt2-promoted facile synthesis of cyclic amidines (2-amino-1-pyrrolines) has been developed via the (3+2)-cycloaddition of cyanamides with donor-acceptorcyclopropanes (DACs). In addition to this, the protocol has been successfully extended to construct a dimerized amidine derivative and gram-scale synthesis with great efficiency.
Rare alkenylalanes are prepared by Cp2TiCl2 or Cp-2*grCl(2) (Cp = eta-C5H5; CP* = eta-C5Me5) catalysed addition of HAlCl2 center dot(THF)(2) to terminal alkynes ((RC)-C-1 CH; R-1 = alkyl). Use of minimum head-volume sealed vials maximises the hydroalumination yields of volatile alkynes. Facile 1,4-addition of the resultant alkenylalanes to unsaturated malonates (RCH)-C-2=C(CO2R3)(2) (R-2 = alkyl, aryl, R-3 = alkyl) is observed providing rapid and convenient access to the addition products. (C) 2014 Elsevier Ltd. All rights reserved.
Process for the preparation of cyclopropylacetylene and its derivatives