Non-coordinating anion, chiral tetra-carbon substituted borates as chiral solvating agents for cationic species

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K05508
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 33020:Synthetic organic chemistry-related
• Research Institution: Niigata University
• Principal Investigator: Tayama Eiji 新潟大学, 自然科学系, 准教授 (90372474)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: キラルボレート / 第四級アンモニウム塩 / キラルアニオン / 不斉識別 / 不斉認識 / 光学活性

Outline of Final Research Achievements

We synthesized chiral borates with four chiral binaphthyl-derived substituents directly introduced onto the boron atom. The borates were applied as chiral recognition agents for quaternary ammonium salts. The optical purities of quaternary ammonium salts were determined by NMR. The chiral borates consist of two basic skeletons: optically active binaphthyl moieties and linker moieties with a boron atom. The structure and chemical properties of the linker were found to be the most important factors in producing various types of chiral borates in good yields. We have discovered a linker that allows modification of the optically active binaphthyl moiety with substituents and provides chiral borates in good yields. Based on this knowledge, we synthesized various types of chiral borates successfully.

Free Research Field

有機合成化学

Academic Significance and Societal Importance of the Research Achievements

近年、非配位性キラルアニオンに着目した研究が盛んに行われている。本研究で扱ったキラルアニオン、キラルボレートは、ホウ素原子上に直接4つの炭素置換基を導入した構造(四炭素置換型)であることから、化学的安定性に優れ、実験上の取扱も容易である。第四級アンモニウム塩の不斉認識剤として機能させた本研究成果は、キラル四炭素置換ボレートを有効利用できた最初の例である。類似の化合物についての過去の合成例と利用例は今日でも尚、限られていることから、今後の研究により新規機能の開拓が見込まれる。