Development of LLX-Type Pincer Ligands for Catalytic Functionalization of C(sp3)-H Bonds

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K14628
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 33020:Synthetic organic chemistry-related
• Research Institution: Kyoto Institute of Technology (2022); Kyushu University (2021)
• Principal Investigator: TORIGOE Takeru 京都工芸繊維大学, 分子化学系, 助教 (80823129)
• Project Period (FY): 2021-04-01 – 2023-03-31
• Keywords: 炭素-水素結合官能基化 / アルカン / 有機ホウ素化合物 / シリル配位子

Outline of Final Research Achievements

In this research, transition metal-catalyzed functionalization of C(sp3)-H bonds of simple molecules such as alkanes was investigated. LLX-type tridentate ligands composed of two neutral ligands (L-type ligands) and an anionic ligand (X-type ligand) were designed. As a model for this study, iridium-catalyzed C(sp3)-H borylation was chosen. Based on N,N-bidentate ligands which are known as typical ligands for the reaction, NNSi pincer ligands were developed and applied to C(sp3)-H borylation. As the result, Ir/NNSi catalyst efficiently promoted the reaction. PNSi pincer ligands were also developed, and Ir/PNSi-catalyzed C(sp3)-H borylation proceeded efficiently.

Free Research Field

有機合成化学

Academic Significance and Societal Importance of the Research Achievements

炭素-水素結合の触媒的な直接変換反応は理想的な分子変換の一つといえるが、その難易度は高く、有効な触媒系の開拓が望まれていた。今回明らかとしたLLX型ピンサー配位子の有効性は、単に有効な配位子を見出したにとどまらず、新たな配位子設計指針となるものであることから、大きな波及効果が期待でき学術的意義は大きい。また、有機分子に普遍的に含まれる炭素-水素結合の触媒的変換は、合成の短工程化や炭化水素資源の有効利用等の実現に寄与するものであり、本研究成果は環境調和型の有機合成への転換を促すものといえる。