Copper-Carbene-Triggered Electrophilic Cyclization of <i>o</i>‑Hydroxyarylenaminones with 3‑Diazoindolin-2-imines: Synthesis of 3‑Indolyl‑4<i>H</i>‑chromen-4-ones and Pyrido[2,3‑<i>b</i>:6,5‑<i>b</i>′]diindoles

The Cu­(II)-catalyzed electrophilic cyclization reaction between o-hydroxyarylenaminones and 3-diazoindolin-2-imines furnished 3-indolyl-4H-chromen-4-ones in moderate to good yields with a broad substrate scope. Several pyrido­[2,3-b:6,5-b′]­diindoles and one pyrazino­[2,3-b:5,6-b′]­diindole were also obtained as byproducts in some cases and tested for their photophysical properties. Pyrido­[2,3-b:6,5-b′]­diindoles exhibited solvent-dependent emission, while pyrazino­[2,3-b:5,6-b′]­diindole emitted strong luminescence with 25.6% quantum yield in cyclohexane.铜(II)催化的邻羟基芳基烯胺酮与3-重氮吲哚啉-2-亚胺之间的亲电环化反应，可合成3-吲哚基-4H-色烯-4-酮类产物，产率中等至优异，且底物适用范围宽泛。部分反应中还会生成吡啶并[2,3-b:6,5-b′]二吲哚类化合物及一例吡嗪并[2,3-b:5,6-b′]二吲哚副产物，研究人员对这些副产物的光物理性质进行了测试。吡啶并[2,3-b:6,5-b′]二吲哚表现出溶剂依赖型发射行为，而吡嗪并[2,3-b:5,6-b′]二吲哚在环己烷中展现出强发光特性，其量子产率可达25.6%。