Ring-closure reaction of 2-benzoylbenzenediazonium salts in 1-butyl-3-methylimidazolium ionic liquids
作者:Takao Okazaki、Hiroyuki Yamamoto、Toshikazu Kitagawa
DOI:10.24820/ark.5550190.p010.195
日期:——
A ring-closure reaction by thermal dediazoniation of 2-substituted benzenediazonium tetrafluoroborates in imidazolium-based ionic liquids was investigated. Dediazoniation of 2-(4-R-benzoyl)benzenediazonium tetrafluoroborates (R = H, Me, OMe, Cl) in ionic liquid [BMIM][TfO] gave 3-R-9-fluorenones as ring-closure products and 2-(4-R-benzoyl)phenyl trifluoromethanesulfonates as substitution products.
研究了 2-取代苯重氮四氟硼酸盐在咪唑基离子液体中热脱重氮的闭环反应。2-(4-R-苯甲酰基)苯重氮四氟硼酸盐 (R = H, Me, OMe, Cl) 在离子液体 [BMIM][TfO] 中的去重氮作用得到 3-R-9-芴酮作为闭环产物和 2-( 4-R-苯甲酰基)苯基三氟甲磺酸盐作为取代产物。[BMIM][Tf2N] 中的脱重氮作用得到 3-R-9-芴酮和 R-C6H4-CO-C6H4-OSO(CF3)(NSO2CF3)。[BMIM][Tf2N] 中闭环产物的产率高于 [BMIM][TfO]。2-苄基苯重氮和 2-苯氧基苯重氮四氟硼酸盐仅在两种离子液体中产生替代产物。DFT 计算表明,在 [BMIM][Tf2N] 中比在 [BMIM][TfO] 中更容易诱导电子从阴离子转移以呈现均裂过程。这种能力可能是导致 [BMIM][Tf2N] 中通过均裂途径的闭环产物产量较高,而通过异裂途径的取代产物产量较小的原因。