A Rh(III)-catalyzed annulation of 2-arylbenzimidazoles with α-diazo carbonyl compounds via C–H activation/carbene insertion/intramolecular cyclization is explored. The switchable product selectivity is achieved by the use of distinct α-diazo carbonyl compounds. Benzimidazole-fused quinolines are obtained through [4 + 2] annulation exclusively when 2-diazocyclohexane-1,3-diones are used, where they act as a C2 synthon. Alternatively, diazonaphthalen-1(2H)-ones merely function as a one-carbon unit synthon to generate a quaternary center through [4 + 1] cyclization to afford spirocyclic benzimidazole-fused isoindole naphthalen-2-ones. A thorough mechanistic study reveals the course of the reaction.

中文翻译：

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苯并咪唑稠合喹啉和螺环苯并咪唑稠合异吲哚的底物控制发散合成


探索了 Rh(III) 催化的 2-芳基苯并咪唑与 α-重氮羰基化合物通过 C-H 活化/卡宾插入/分子内环化的成环反应。可切换的产物选择性是通过使用不同的α-重氮羰基化合物来实现的。仅当使用 2-重氮环己烷-1,3-二酮时，苯并咪唑稠合喹啉才通过 [4 + 2] 环化获得，其中它们充当 C2 合成子。或者，重氮萘-1(2H)-酮仅充当一碳单元合成子，通过[4 + 1]环化产生季中心，得到螺环苯并咪唑稠合异吲哚萘-2-酮。彻底的机理研究揭示了反应过程。