Investigations on the properties of medium-sized ring compounds directed to the development of their synthetic strategies

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05034
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 33010:Structural organic chemistry and physical organic chemistry-related
• Research Institution: Gunma University
• Principal Investigator: Muraoka Takako 群馬大学, 大学院理工学府, 教授 (40400775)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 中員環化合物 / ルイス酸性元素 / 分極性結合 / 環拡大

Outline of Final Research Achievements

Medium-sized ring compounds containing Lewis acidic elements are one of the unexplored research areas, as the synthesis method has not been established. When we subjected a gallium compound to a reaction that is generally considered a method for synthesizing 5-membered ring diene compounds, we found that, contrary to expectations, a 10-membered ring tetraene derivative was produced. The reason for the change in the product selectivity from 5-membered ring diene to 10-membered ring tetraene is that the gallium-carbon bonds are polarized and bond cleavage and bond formation easily proceed during the reaction, and that the 10-membered ring contains a stabilizing interaction between gallium and sp2 carbon atoms. Furthermore, when electronic and steric perturbations were applied to the 10-membered ring tetraene, ring contractions into 5- and 9-membered rings took place.

Free Research Field

有機金属化学

Academic Significance and Societal Importance of the Research Achievements

酸素や窒素などの含ヘテロ原子中員環化合物は，様々な員環数の化合物が合成され，陽イオン識別などに利用されるなど，学術的，実践的研究が盛んにおこなわれている。クラウンエーテル類縁体は，孤立電子対を含む電子豊富なヘテロ元素が大きな結合定数を有する陽イオンと優先的に相互作用することで陽イオンを識別している。これらの概念と異なり，中員環内に電子不足のルイス酸性元素を導入して陰イオンを識別する研究は，皆無である。本研究での成果，さらに本研究概念を他のルイス酸性元素化合物に応用することで，含ルイス酸性元素中員環化合物を自在に設計・合成し，陰イオン識別をはじめとする応用利用への可能性が拓かれる。