Functionalization of Unactivated Alkenes through Iridium-Catalyzed Borylation of Carbon−Hydrogen Bonds. Mechanism and Synthetic Applications
作者:Vilhelm J. Olsson、Kálmán J. Szabó
DOI:10.1021/jo9014694
日期:2009.10.16
methylimidazole and DBU, the iridium-catalyzed borylation led to formation of allyl boronates, which reacted with aldehydes in a one-pot sequence affording stereodefined homoallylic alcohols. Cycloalkenes without additives as well as acyclic substrates gave vinylic boronates, which were coupled with organohalides in a Suzuki−Miyaura sequence. By this process allylic and vinylic silabutadiene derivatives
本文介绍了一种有效的碳-碳键形成反应,该反应基于未活化烯烃的碳-氢键官能化。此过程基于铱催化烯烃的硼化反应,然后进行碳-碳键形成反应,从而原位生成烯丙基和乙烯基硼酸酯。对于环烯烃,可以有效地控制碳氢键官能化的选择性。通过使用添加剂,例如甲基咪唑和DBU,铱催化的硼酸酯化反应会生成烯丙基硼酸酯,后者与醛按一锅法反应生成立体定义的均烯丙基醇。没有添加剂以及无环底物的环烯烃会生成乙烯基硼酸酯,并以Suzuki-Miyaura序列与有机卤化物偶联。通过该方法,可以从烯丙基硅烷制备具有优异的区域选择性和立体选择性的烯丙基和乙烯基的硅丁二烯衍生物。通过同位素标记实验,测量动力学同位素效应以及研究添加剂对工艺选择性的影响,探索了基于硼化反应的碳氢键官能化机理。可以得出结论,该反应是通过脱氢硼化反应机理进行的,该机理显示出与钯催化的Heck偶联反应相似的特征。测量动力学同位素效应并研究添加剂对工艺选择性的