Al-Huniti Mohammed H, Lu Shuiyu, Pike Victor W, Lepore Salvatore D
Department of Chemistry, Florida Atlantic University, Boca Raton, Florida 33431.
Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1003.
J Fluor Chem. 2014 Feb 1;158:48-52. doi: 10.1016/j.jfluchem.2013.12.005.
Here we aimed to explore the feasibility of enhancing the fluorination of organosilanes by appending potassium-chelating groups to the substrates. For this purpose, eight organosilanes were prepared in which a linear or cyclic leaving group, with putative potassium-chelating ability, was attached covalently to a congested silicon atom via an ether linkage to serve as a potential nucleophilic assisting leaving group (NALG). Organosilicon-NALGs with expected strong potassium-chelating capability enhanced reactions with potassium fluoride in acetonitrile to produce organofluorosilanes without any need to separately add phase transfer reagent. Similar rate enhancements were also observed with cyclotron-produced [F]fluoride ion ( = 109.7 min, β = 97%) in the presence of potassium carbonate in MeCN-0.5% HO. This study found that metal-chelating NALG units can accelerate fluorination and radiofluorination reactions at sterically crowded silicon atoms.
在此，我们旨在探讨通过在底物上连接钾螯合基团来增强有机硅烷氟化反应的可行性。为此，制备了八种有机硅烷，其中具有假定钾螯合能力的线性或环状离去基团通过醚键共价连接到拥挤的硅原子上，用作潜在的亲核辅助离去基团（NALG）。具有预期强钾螯合能力的有机硅-NALG增强了与乙腈中氟化钾的反应，无需单独添加相转移试剂即可生成有机氟硅烷。在MeCN-0.5%HO中碳酸钾存在的情况下，使用回旋加速器产生的[F]氟离子（ = 109.7分钟，β = 97%）时也观察到了类似的速率提高。本研究发现，金属螯合NALG单元可以加速在空间拥挤的硅原子上的氟化和放射性氟化反应。
