Chen Liang-Yu, Li Junqi
Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.
J Org Chem. 2023 Jul 21;88(14):10252-10256. doi: 10.1021/acs.joc.3c00700. Epub 2023 Jul 5.
The skeletal editing of dibenzolactones to fluorenes by Ni- or Pd-catalyzed decarboxylation is reported. In contrast to previously reported intramolecular decarboxylative couplings, inductively electron-withdrawing substituents on the aryl carboxylate moiety and metal additives are not required. The decarboxylation reaction proceeds cleanly and can be applied to the skeletal editing of a natural product analogue. Mechanistic observations are consistent with stabilization of the carboxylate-ligated Ni complex over the Ni-carboxylate ion pair, which is the key factor in promoting the challenging decarboxylation step in the catalytic cycle.
据报道，通过镍或钯催化的脱羧反应可将二苯并内酯骨架编辑为芴。与先前报道的分子内脱羧偶联反应不同，芳基羧酸酯部分上不需要吸电子取代基和金属添加剂。脱羧反应进行得很彻底，可应用于天然产物类似物的骨架编辑。机理研究结果与羧酸根配位的镍络合物比镍-羧酸根离子对更稳定相一致，这是催化循环中促进具有挑战性的脱羧步骤的关键因素。
