High-Yield Thermolytic Conversion of Imidazolium Salts into Arduengo Carbene Adducts with BF3 and PF5статьяИсследовательская статья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 6 декабря 2018 г.
Аннотация:Thermolysis of 1-ethyl-3-methyl-1H-imidazolium tetrafluoroborate (1) and 1,3-dimethyl-1H-imidazolium hexafluorophosphate (3) under reduced pressure eliminates HF to furnish the BF3 and PF5 adducts of the corresponding Arduengo carbenes (2 and 4) in high yields. The intuitively anticipated imidazole N adducts with BF3 and/or PF5 arising from elimination of alkyl fluorides are not detected at all. These observations represent the first examples of a direct bond rearrangement of the type [C−H] + E−F → [C−E] + H−F (E = B, P). DFT computational studies suggest a single-step mechanism for the reaction 1 → 2 + HF. Lower yield thermolysis of a 1,2,3-trimethyl-1H-imidazolium hexafluorophosphate (11) into [(1,3-dimethyl-1H-imidazolium-2-yl)methyl]pentafluorophosphate (12) supports the generality of this transformation.