1999 Fiscal Year Final Research Report Summary
Development of Methodology in the Chemo- and Stereoselective Fluorination Using HP Molten Salts for the Preparation of Highly Functionalized Materials.
| Project/Area Number |
09450329
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
有機工業化学
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
YONEDA Norihiko Hokkaido Univ., Fac, of Eng., Pro., 大学院・工学研究科, 教授 (50001219)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIYAMA Tatsuo Thochem Products Co. Ltd., the general manager of research and development, 研究開発部, 研究部長(研究職)
FUKUHARA Tsuyoshi Hokkaido Univ., Fac. Of Eng., Instructor, 大学院・工学研究科, 助手 (50238507)
HARA Shoji Hokkaido Univ., Fac. Of Eng., Associate Pro., 大学院・工学研究科, 助教授 (20109490)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Hydrogen Fluoride / HF Molten salts / Iodoarene Difluoride / Iodonium Salt / Fluorealkene / Fluoroether / Fluorination Electrochemical / Deaminative Fluorination |
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| Research Abstract |
1) The fluorination of organic compounds using HF molten salts has been investigated. EtィイD23ィエD2N-nHF and EtィイD24ィエD2NF-nHF was found to be a useful fluorinating agent in the hydrofluorination, halofluorination, fluorinative cyclization, electrochemical partial fluorination, and various fluorinations of organic compounds.
2) Areneiodine difluoride (ArlFィイD22ィエD2) can be readily prepared electrochemically from the corresponding ArI in 5HF-EtィイD23ィエD2N electrolyte. Electrochemically generated (EG)ArIFィイD22ィエD2 is a useful reagent for the fluorination of organic compounds. For example, α-fluorination of β-keto-esters(1) with EG ArIFィイD22ィエD2 took place readily in the presence of 5HF-EtィイD23ィエD2N solution. Indirect electrochemical fluorination of 1 with ArI as mediator has been also successfully carried out by in-cell method to produce α-fluoro-β-keto-esters. Terminal and cyclic alkenes reacted with EG-ArIFィイD22ィエD2 in 5HF-EtィイD23ィエD2N to give vic-difluoro products selectively. On the othe
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r hand, alkyl substituted cyclic alkenes took place fluorinative ring-contraction to afford gem-difluoro cycloalkanes. Reaction of terminal aikynes with EG-ArIFィイD22ィエD2 in 5HF-EtィイD23ィエD2N afforded E-2-fluoroalkenyl-iodonium salts (2) regio- and stereo-selectively. 2 was found to be very useful precursor for the stereo-selective synthesis of various α-fluoroalkenes, which are interesting from the view point of introduction of a fluorine atom into the double bond of natural products and may be expected to have different pharmacological properties from the original compounds.
3) A novel electrochemical partial fluorination (ECF) of conjugated esters and styrenes took place to afford vic-difluorinated compounds. Anodic oxidation of benzylic compounds in CHィイD22ィエD2ClィイD22ィエD2using HF molten salts allowed to introduce a fluorine atom at α position of electron withdrawing group in the substrate. Reaction can be elucidated as ECEC mechanism.
4) In the presence of EtィイD23ィエD2N-5HF electrolyte, anodic fluorination of phenols (3) successfully took place to afford 4, 4-difluorocyclohexa-2, 5-diene-1-ones. This compounds readily convert to p-fluorophenols in good yields by the subsequent reduction with Zn in an acidic aqueous solutions. We revealed some novel information on the oxidation mechanism of 1, which is well supported by the cyclic voltammogram (CV) of 1 in EtィイD23ィエD2N-5HF. Less
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