dibenzothiophenes, undergo nucleophilic aromatic substitution with anilines intermolecularly and then intramolecularly to yield the corresponding carbazoles in a single operation. The “aromaticmetamorphosis” of dibenzothiophenes into carbazoles does not require any heavy metals. This strategy is also applicable to the synthesis of indoles. Since electron‐deficient thiaarene dioxides exhibit interesting reactivity
通过母体二苯并噻吩的氧化容易制备的二苯并噻吩二氧化物在一次操作中在分子内然后在分子内经历苯胺的亲核芳香取代,然后生成分子内相应的咔唑。二苯并噻吩向咔唑的“芳香变形”不需要任何重金属。该策略也适用于吲哚的合成。由于缺电子的硫杂芳烃二氧化物表现出有趣的反应性,而相应的富电子氮杂芳烃则未观察到,因此,二氧化硫杂ar特定反应与基于S N Ar的芳族变态反应的结合,使得无过渡金属的结构成为可能。难以制备咔唑。
Synthesis of Spirocyclic Diarylfluorenes by One-Pot Twofold S<sub>N</sub>Ar Reactions of Diaryl Sulfones with Diarylmethanes
tetraarylmethanes in a single operation. The transformation would proceed via an intermolecular SNAr reaction of the dioxides with cyclic diarylmethylpotassium followed by intramolecular SNAr cyclization. This straightforward strategy provides a wide range of spirocyclic diarylfluorenes including unusual ones that are otherwise difficult to synthesize.
在KN(SiMe 3)2存在下用环状二芳基甲烷处理二苯并噻吩二氧化物导致在单个操作中形成芴基螺环四芳基甲烷。所述转化将通过二氧化物与环状二芳基甲基钾的分子间S N Ar反应,然后进行分子内S N Ar环化而进行。这种简单的策略可提供多种螺环二芳基芴,包括难于合成的不寻常的螺环。
Synthesis of
<i>N</i>
‐Alkyl and
<i>N‐H</i>
‐Carbazoles through S
<sub>N</sub>
Ar‐Based Aminations of Dibenzothiophene Dioxides
作者:Atsushi Kaga、Keisuke Nogi、Hideki Yorimitsu
DOI:10.1002/chem.201903916
日期:2019.11.22
Alkyl amines have become available for the synthesis of diverse N-alkyl carbazoles through twofold SN Ar aminations of dibenzothiophene dioxides by using alkali metal bases. Of particular importance is the choice of counter cations on alkali metal bases, that is, i) the use of Li base for the efficient intermolecular reaction and ii) the sequential addition of heavier alkali metal bases (Na, K, or