A selective oxidative [4+2] annulation of alkenes with imidazo-fused heterocycles has been developed by using the synergistic combination of photoredox and cobaloxime catalysts. It allows facile access to various imidazole-fused polyaromatic scaffolds accompanied by H₂ evolution. This protocol features high regioselectivity as well as a broad substrate scope. Detailed mechanistic studies indicate that twice the electron/H transfer processes facilitated by this catalytic system achieve the annulation π-extension of imidazo-fused heterocycles with alkenes.

中文翻译：

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光氧化还原-钴肟催化咪唑稠合杂环与烯烃的选择性氧化脱氢[4+2]环化

通过使用光氧化还原和钴肟催化剂的协同组合，开发了烯烃与咪唑稠合杂环的选择性氧化[4+2]环化。它允许轻松获得各种咪唑稠合的聚芳族支架，并伴有 H _{2 的}演化。该方案具有高区域选择性和广泛的底物范围。详细的机理研究表明，该催化系统促进的电子/H转移过程的两倍实现了咪唑并稠合杂环与烯烃的环化π延伸。