π-Extended DPCB for Activation-Free Homogeneous Gold Catalysis
π-Extended DPCB for Activation-Free Homogeneous Gold Catalysis
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DOI：
10.1002/cctc.201402158
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发表时间：
2014-08-01
期刊：
影响因子：
4.5
通讯作者：
Mikami, Koichi
中科院分区：
文献类型：
--
作者：
Ito, Shigekazu;Nanko, Masaki;Mikami, Koichi
以3,4-二（2,4,6-三叔丁基苯基）-3,4-二膦烯环丁烯（DPCB）为配体的双[氯金(I)]配合物的催化性能可以通过适当扩展偶联得到改善。如果在动力学稳定的DPCB骨架的1,2位上加入1-萘基取代基，则DPCB-双（氯金）配合物在1,6-炔的分子间烷氧环化反应中具有较高的催化活性，而不需要Ag助催化剂的激活。1,2-二芳基取代的二氯联苯衍生物的DFT计算表明，适当的LUMO能级的能量还原和配体结构的空间结构特征是高催化活性的重要因素。优化后的1-萘取代dpcb -氯金(I)配合物在温和条件下通过末端乙炔和烯基的活化以及末端乙炔的水化作用催化分子内环化，得到杂环结构。
The catalytic properties of bis[chlorogold(I)] complexes that bear the 3,4-bis(2,4,6-tri-tert-butylphenyl)-3,4-diphosphinidene cyclobutene (DPCB) ligand could be improved by suitable extension of the pi-conjugation. If the 1-naphthyl substituent was employed in the 1,2-positions in the kinetically stabilized DPCB skeleton, high catalytic activity of the DPCB-bis(chlorogold) complex was induced in the intermolecular alkoxycyclization of 1,6-enyne without activation by a Ag cocatalyst. DFT calculations of the 1,2-diaryl-substituted DPCB derivatives indicated that both suitable energetic reduction of the LUMO level and steric characteristics of the ligand structure are important for the high catalytic activity. The optimized 1-naphthyl-substituted DPCB-chlorogold(I) complex was further employed for catalytic intramolecular cyclizations to afford heterocyclic structures by the activation of terminal acetylene and allene moieties and the hydration of terminal acetylene under the mild conditions.