Intramolecular Anionic Diels−Alder Reactions of 1-Aryl-4-oxahepta-1,6-diyne Systems in DMSO
作者:Takayuki Kudoh、Tomoko Mori、Mitsuhito Shirahama、Masashi Yamada、Teruhiko Ishikawa、Seiki Saito、Hisayoshi Kobayashi
DOI:10.1021/ja066485u
日期:2007.4.1
Base-promoted cycloaddition reactions of 1-aryl- or 1-aryl-7-substituted-4-oxahepta-1,6-diyne systems in DMSO have proven to involve an anionic intramolecular Diels-Alder process taking place even at room temperature in spite of the reaction suffering from temporary disruption of aromaticity. Although initially formed alpha-arylallenide anion can be protonated by DMSO, it can be back to the allenide
已证明 DMSO 中 1-芳基-或 1-芳基-7-取代的-4-oxahepta-1,6-二炔系统的碱促进环加成反应涉及阴离子分子内 Diels-Alder 过程,即使在室温下暂时破坏芳香性的反应。虽然最初形成的 α-芳基丙二烯阴离子可以被 DMSO 质子化,但它可以恢复为丙二烯阴离子,可能是因为 α-芳基丙二烯和 DMSO 之间的酸度差异很小。α-芳基丙二烯阴离子与 α-芳基取代基结合可以构成阴离子二烯结构,该结构经历涉及 C(6)-yne 部分的分子内狄尔斯-阿尔德反应,这个过程非常快,可能是因为 HOMO-1 水平增加阴离子二烯,如 DFT 计算所示。多样化的取代萘,