Synthesis of potassium 4-(1-azol-1-yl)-2,3,5,6-tetrafluorophenyltrifluoroborates from K[C6F5BF3] and alkali metal azol-1-ides. The dramatic distinction in nucleophilicity of alkali metal azol-1-ides and dialkylamides
作者:Anton Yu. Shabalin、Nicolay Yu. Adonin、Vadim V. Bardin、Oksana P. Taran、Artemiy B. Ayusheev、Valentin N. Parmon
DOI:10.1016/j.jfluchem.2013.07.011
日期:2013.12
Nucleophilic substitution of fluorine atom in K[C6F5BF3] with alkali metal azol-1-ides in polar aprotic solvent (DMF, DMSO) at 60–130 °C gives potassium 4-(azol-1-yl)-2,3,5,6-tetrafluorophenyltrifluoroborates, K[4-AzC6F4BF3] (AzH = pyrrole, pyrazole, imidazole, indole, and benzimidazole). Unexpectedly, diethylamine and morpholine do not react with K[C6F5BF3] under the same conditions while pentafluorobenzene
在60-130°C的极性非质子溶剂(DMF,DMSO)中,用碱金属氮杂-1-酸将K [C 6 F 5 BF 3 ]中的氟原子亲核取代,得到4-(氮杂-1-基)-钾2,3,5,6-四氟苯基三氟硼酸酯,K [4-AzC 6 F 4 BF 3 ](AzH =吡咯,吡唑,咪唑,吲哚和苯并咪唑)。出乎意料的是,二乙胺和吗啉在相同条件下不会与K [C 6 F 5 BF 3 ]反应,而五氟苯和R 2 NC 6 F 4 H在150°C时形成。K [C 6 F 5 BF 3的反应用二甘醇二甲醚或DMSO中的Na [NR 2 ]进行类似的过程。推测的原因是仲胺和碱金属二烷基酰胺的亲核性都较低,这会导致与K [C 6 F 5 BF 3 ]的破坏性副反应,而不是其氨基脱氟。模型底物C 6 F 5 Ph与吲哚钠/吗啉化钠的竞争性亲核氨基脱氟作用证实了这一点。