Synthesis and unique catalytic reactivity of metal complexes with chelate- type silyl ligands connected by xanthene

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Design and synthesis of supporting ligands for transition-metal complexes are significant as an efficient method for development of new metal complex catalysts for organic synthesis. Metal complexes bearing chelate-type silyl supporting ligands are expected to show high catalytic performance toward activation of inert bonds such as C-H due to the strongly a-donating and trans-labilizing properties of their silyl ligand moieties. This article describes recent progress of synthesis and catalysis of transition-metal complexes bearing a xanthene-based bis (silyl) supporting ligand "xantsil", developed by our previous study, and a related silyl(phosphine)xanthene chelate ligand "xantSiP". These complexes were synthesized straightforwardly by reactions of (hydrosilyl) xanthene derivatives as ligand precursors with low-valent metal complexes via Si-H activation and ligand substitution. As a prominent result, the reaction of arylalkynes with hydrosilanes catalyzed by 16-electron ruthenium-xantsil complexes with bulky trialkylphosphine was found to give 2-silylstyrenes via ortho-C-H silylation and trans-selective hydrogenation (ortho-C-H silylation/hydrogenation). On the other hand, when catalysts with triaminophosphine instead of trialkylphosphine were used for the reaction, 2,a-bis (silyl) styrenes were formed in most cases via ortho-C-H silylation and trans-selective hydrosilylation (ortho-C-H silylation/hydrosilylation). These novel C-H silylation reactions proceeded under mild conditions (room temp. ~ 70 °C).

Original languageEnglish
Pages (from-to)1301-1309
Number of pages9
JournalYuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry
Issue number12
Publication statusPublished - 2018


  • C-H silylation
  • Chelate ligand
  • Coordina-tively-unsaturated complex
  • Hydrogenation
  • Hydrosilylation
  • Metal complex catalyst
  • Silyl ligand
  • Xanthene backbone

ASJC Scopus subject areas

  • Organic Chemistry


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