Catalytic defluorination of polyfluoro-compounds inducing substitution reactions utilizing affinity between silicon and fluorine atoms

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K17899
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Synthetic chemistry
• Research Institution: Ritsumeikan University (2018); Osaka University (2016-2017)
• Principal Investigator: Kikushima Kotaro 立命館大学, 薬学部, 助教 (40609880)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: フッ素 / 水素化反応 / 置換反応 / ケイ素

Outline of Final Research Achievements

Hydrodefluorination of polyfluoroarenes proceeded in the presence of hydrosilane and a catalytic amount of fluoride salt. Various polyfluoroarenes could be employed as a substrate to afford the corresponding hydrodefluorination products. We carried out the stoichiometric reactions and computational chemistry to study the reaction mechanism. Hydrosilicates, which were generated in situ from hydrosilane and fluoride, are key intermediates for the hydrodefluorination. Moreover, the reaction proceeds through concerted aromatic nucleophilic substitution reaction.
When ethynylsilanes and thienylsilanes were used as a organosilicon compound, fluorine atoms attached to alekne moiety of polyfluoroalkenes were substituted with the corresponding carbon functional groups in the presence of fluoride salt.

Free Research Field

有機合成化学

Academic Significance and Societal Importance of the Research Achievements

含フッ素有機化合物は医薬品や農薬、機能性材料の創出において注目されているが、その合成は必ずしも容易ではない。本研究では含フッ素有機化合物の新たな合成法の創出を目的とし、フッ化物塩と有機ケイ素化合物を用いたポリフルオロ化合物の触媒的脱フッ素水素化および置換基導入反応を開発した。遷移金属を用いない触媒的脱フッ素水素化反応は前例がない。従来の遷移金属によるC-F 結合活性化で問題となる金属－フッ素間の強い親和性を逆に活かし、パーフルオロ化合物との付加脱離反応に組み込んだ。新たな還元的水素化反応や炭素－炭素結合形成反応であり、医薬品や機能性材料を合成する際の手段の一つとなる。