立体选择性炔烃半氢化是制备烯烃的有吸引力的方法,烯烃是合成的关键组成部分。对于最具原子经济性的还原剂二氢(H 2 ),仅公开了少数用于具有挑战性的E-选择性炔烃半氢化的催化剂,每种催化剂都具有独特的底物范围特征。在这里,我们表明,市售的镍催化剂促进了多种取代内炔的E-选择性炔烃半氢化。这产生了一个简单且广泛适用的整体方案,用于使用 H 2立体选择性地访问E-烯烃,这可以作为通用的合成方法。
“Anti-Michael addition” of Grignard reagents to sulfonylacetylenes: synthesis of alkynes
作者:Francisco Esteban、Lazhar Boughani、José L. García Ruano、Alberto Fraile、José Alemán
DOI:10.1039/c7ob00783c
日期:——
In this work, the addition of Grignardreagents to arylsulfonylacetylenes, which undergoes an “anti-Michael addition”, resulting in their alkynylation under very mild conditions is described. The simplicity of the experimental procedure and the functional group tolerance are the main features of this methodology. This is an important advantage over the use of organolithium at −78 °C that we previously
The rates of monometallation of alkylphenylacetylenes
作者:James Y. Becker
DOI:10.1016/s0022-328x(00)84192-3
日期:1977.2
Alkylphenylacetylenes, C6H5CCCH2R, have been metallated at the propargylic positions with an excess of n-butyllithium in diethyl ether at 0°C. Mono- and di-silyl derivatives have been isolated by quenching the metallation mixtures with Me3SiCl at different times. Pseudo-first order rate constants have been calculated for the monometallation from the rate of formation of the silylated products. A Taft
A Co(acac)2/POL‐Xantphos@10PPh3‐catalyzed hydrosilylation of unsymmetrical internal alkynes with Ph2SiH2 has been developed for the synthesis of highly selective syn‐α‐vinylsilane products. Furthermore, terminal alkynes were also used and gave the products with excellent regioselectivity and a wide functional group tolerance. Because this porous organic polymer combines the selectivity and activity
Nickel-catalyzed cross-coupling of primary alkyl halides with phenylethynyl- and trimethylsilyethynyllithium reagents
作者:Guoqiang Xu、Xiaoyan Li、Hongjian Sun
DOI:10.1016/j.jorganchem.2011.05.017
日期:2011.9
coupling system is described which is promoted by a well-defined and moisture-stable pincer complex [NiClC6H3-2,6-(OPPh2)2}] (1). Non-activated alkyl halides could be efficiently coupled with phenylethynyl- and trimethylsilylethynyllithium reagents at room temperature. Compared to the alkylation of primary alkyl halides with alkynyllithium reagents in literatures, this method requires milder conditions
描述了一种高效的烷基-炔基偶联体系,该体系由定义明确且耐湿的夹钳络合物[NiCl C 6 H 3 -2,6-(OPPh 2)2 }](1)促进。未活化的烷基卤化物可以在室温下与苯基乙炔基-和三甲基甲硅烷基乙炔基锂试剂有效偶联。与文献中使用炔基锂试剂将卤代烷基卤化物进行烷基化相比,该方法需要较温和的条件(室温)并且进展迅速。这项研究将使这些易于获得的炔基锂试剂对于有机合成更加有用。
Xanthate-mediated synthesis of (<i>E</i>)-alkenes by semi-hydrogenation of alkynes using water as the hydrogen donor
作者:Xianglin Luo、Xiuwen Chen、Lu Chen、Kun Zhang、Yibiao Li
DOI:10.1039/c9cc00128j
日期:——
Semi-hydrogenation of alkynes is one of the most widely used methods for obtaining alkenes in laboratory preparation and in industry. Transition metal catalysts have been extensively studied for this transformation, but the tolerance of functional groups, such as pyridine, –OH, –NH2, –Bpin, and halides, and the toxicity of the trace amount of transition metal catalysts are still highly challenging