开发用于环境友好的有机转化的催化剂是一个非常活跃的研究领域。迄今为止报道的大多数催化剂都是基于过渡金属配合物。近年来,已经报道了由主族金属化合物催化的例子。在此,我们报告了一系列镁钳配合物,并通过 NMR 和 X 射线单晶衍射对其进行了表征。研究了通过芳构化/脱芳构化金属-配体合作对 H 2的可逆活化。利用所获得的配合物,在无碱条件下证明了前所未有的均相主族金属催化炔烃的半氢化和烯烃的氢化,得到Z-烯烃和烷烃分别作为产物,具有优异的收率和选择性。对照实验和 DFT 研究揭示了金属-配体合作参与氢化反应。该研究不仅为镁催化的炔烃半加氢和烯烃加氢提供了新途径,而且为主族金属配合物催化的其他化合物加氢提供了机会。
Efficient Copper-Free PdCl2(PCy3)2-Catalyzed Sonogashira Coupling of Aryl Chlorides with Terminal Alkynes
摘要:
[GRAPHICS]Under copper-free conditions and with Cs2CO3 as a base, PdCl2(PCy3)(2) showed high catalytic activity for cross-coupling of electron-rich, electron-neutral, and electron-deficient aryl chlorides with a variety of terminal alkynes in DMSO at 100-120 degrees C affording internal arylated alkynes in good to excellent yields.
The copper-catalyzeddecarboxylative reactions of alkynyl carboxylic acids with aryl halides were performed under relatively mild reaction conditions. Benzofurans could be further prepared smoothly by a one-pot domino protocol on the basis of decarboxylativecross-coupling of 2-iodophenol.
carbocation‐driven reactions has been identified which allows for the chemo‐, regio‐, and stereoselective addition of nucleophiles to alkynes—assisted vinyl cation formation—enabled by a Li+‐based supramolecular framework. Mechanistic analysis of a model complex (Li2NTf2+⋅3 H2O) confirms that solely the formation of a complex between the incoming nucleophile and the transition state of the alkyne protonation
Allylic alcohol synthesis by Ni-catalyzed direct and selective coupling of alkynes and methanol
作者:Herong Chen、Zhijun Zhou、Wangqing Kong
DOI:10.1039/d1sc02625a
日期:——
nickel-catalyzed direct coupling of alkynes and methanol, providing direct access to valuable allylicalcohols in good yields and excellent chemo- and regioselectivity. The approach features a broad substrate scope and high atom-, step- and redox-economy. Moreover, this method was successfully extended to the synthesis of [5,6]-bicyclic hemiacetals through a cascade cyclization reaction of alkynones and methanol
Trisubstituted olefin synthesis <i>via</i> Ni-catalyzed hydroalkylation of internal alkynes with non-activated alkyl halides
作者:Xiao-Yu Lu、Mei-Lan Hong、Hai-Pin Zhou、Yue Wang、Jin-Yu Wang、Xiu-Tao Ge
DOI:10.1039/c8cc01577e
日期:——
The stereoselective synthesis of tri-substituted alkenes is challenging. Herein, we report a Ni-catalyzed regio- and stereo-selective hydroalkylation of internal alkynes with non-activated alkylhalides. This method does not use any sensitive organometallic reagents and shows good functional group compatibility, which enables the efficient synthesis of many tri-substituted olefins from readily available
Synthesis of trisubstituted olefins via nickel-catalyzed decarboxylative hydroalkylation of internal alkynes
作者:Xiao-Yu Lu、Jing-Song Li、Mei-Lan Hong、Jin-Yu Wang、Wen-Jing Ma
DOI:10.1016/j.tet.2018.10.037
日期:2018.12
A novel NiH-catalyzed decarboxylative hydroalkylation of internal alkynes has been developed. Trisubstitutedolefins were obtained in moderate to good yields with good regioselectivities. The reaction involves cis addition of NiH to the internal alkyne. The reaction shows good functional-group tolerance.