Palladium Porphyrin Catalyzed Hydrogenation of Alkynes: Stereoselective Synthesis of cis-Alkenes
摘要:
(Tetraphenylporphyrin)palladium was developed as a catalyst for the chemoselective and stereoselective hydrogenation of alkynes to cis-alkenes by the syn-addition of hydrogen. Alkynes containing various functional groups were tolerated in the reaction, which gave the corresponding cis-alkenes in good to excellent yields.
An analysis of the influences dictating regioselectivity in platinum-catalyzed hydrosilylations of internal alkynes
作者:Douglas A. Rooke、Zachary A. Menard、Eric M. Ferreira
DOI:10.1016/j.tet.2014.03.012
日期:2014.7
A full account of our studies on internal alkyne hydrosilylations using platinum catalysis is described. We demonstrate that these transformations are highly governed by the electronic characteristics of the alkyne substituents, wherein the hydride will add preferentially to the more electron-deficient alkyne carbon. The steric and coordinative capabilities of the substituents influence the selectivity
完整介绍了我们对使用铂催化的内部炔烃氢甲硅烷基化的研究。我们证明,这些转变高度受炔烃取代基的电子特性支配,其中氢化物将优先添加至电子欠缺的炔烃碳上。取代基的空间和配位能力对选择性的影响程度要小得多,其中丙炔醇是唯一的例外。硅烷的选择在某些情况下是相关的。特定的硅烷将提供较高的区域选择性,而其他的则选择性要低得多。最终,使用13 C NMR化学位移数据可以完全预测加成的区域选择性,从而将这种反应性纳入目标反应设计中。
Copper catalyzed hydrodefluorination of propargylic gem-difluorides with “triple bonds migration”
作者:Ting Wang、Zhirong Li、Jiayi Hu、Tao Wu
DOI:10.1016/j.tet.2022.132897
日期:2022.8
A copper catalyzed hydrodefluorination of propargylic gem-difluorides was reported, in which two C–F bonds was reductive converted to C–H bonds and a new alkyne product was afforded with the triple bond migrating one methylene. Mechanistic studies show that the products are achieved by stepwise C–F bond reductive hydrogenation, and an allenyl monofluoride is proposed to be one of the active intermediates