A highly regioselective, carbazole based Electron Donor Acceptor (EDA) catalyzed synthesis of biaryl and aryl–heteroaryl compounds is described. Various indole and carbazole derivatives were screened for the Homolytic Aromatic Substitution (HAS) reaction. Tetrahydrocarbazole (THC) was very efficient for the HAS transformation and proceeded via a complex formation between diazonium salt and electron rich tetrahydrocarbazole. The UV-Vis spectroscopy technique has been used to confirm the complex formation. The in situ generated EDA complex even in a catalytic amount is found to be efficient for the Single Electron Transfer (SET) process without any photoactivation. Biaryl compounds, 2-phenylfuran, 2-phenylthiophene, and 2-phenylpyrrole and bioactive compounds such as dantrolene and canagliflozin have been synthesized in moderate to excellent yields.

中文翻译：

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咔唑基电子给体受体（EDA）催化合成联芳基和芳基-杂芳基化合物

描述了一种高度区域选择性的，基于咔唑的电子给体受体（EDA）催化的联芳基和芳基-杂芳基化合物的合成。筛选了各种吲哚和咔唑衍生物进行均相芳香取代（HAS）反应。四氢咔唑（THC）对于HAS转化非常有效，并通过重氮盐与富电子的四氢咔唑之间的络合物形成进行。紫外-可见光谱技术已用于确认复合物的形成。在原位发现即使催化量也能生成的EDA络合物对于单电子转移（SET）过程非常有效，并且没有任何光活化作用。联芳基化合物，2-苯基呋喃，2-苯基噻吩和2-苯基吡咯以及生物活性化合物（例如丹特林和canagliflozin）的合成产率中等至优异。