Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy , University of Regensburg , D-93040 Regensburg , Germany.
J Am Chem Soc. 2018 Mar 7;140(9):3198-3201. doi: 10.1021/jacs.7b13448. Epub 2018 Feb 21.
The ligand-controlled Markovnikov and anti-Markovnikov hydrocarboxylation of styrenes with atmospheric pressure of CO at room temperature using dual visible-light-nickel catalysis has been developed. In the presence of neocuproine as ligand, the Markovnikov product is obtained exclusively, while employing 1,4-bis(diphenylphosphino)butane (dppb) as the ligand favors the formation of the anti-Markovnikov product. A range of functional groups and electron-poor, -neutral, as well as electron-rich styrene derivatives are tolerated by the reaction, providing the desired products in moderate to good yields. Preliminary mechanistic investigations indicate the generation of a nickel hydride (H-Ni) intermediate, which subsequently adds irreversibly to styrenes.
双可见光-镍催化体系在室温常压下实现了苯乙烯的配体控制的 Markovnikov 和反 Markovnikov 氢羧化反应。在邻菲咯啉作为配体的存在下，仅得到 Markovnikov 产物，而使用 1,4-双（二苯基膦）丁烷（dppb）作为配体有利于反 Markovnikov 产物的形成。一系列官能团和缺电子、中性和富电子的苯乙烯衍生物都能耐受反应，以中等至良好的收率得到所需产物。初步的机理研究表明，生成了镍氢化物（H-Ni）中间体，它随后不可逆地加成到苯乙烯上。
