1H-indole-3-carboxamide

Cobalt-catalyzed C-H Activation and Isocyanide Insertion of 1H-indole-3-amides

Wei, Ping, et al. Journal of Catalysis, 2022, 414, 349-355.

This study presented a cobalt-catalyzed activation of C-H bonds and isocyanide incorporation in 1H-indole-3-carboxamides, enabling the versatile synthesis of two distinct types of indole-related compounds.
Specifically, employing MgSO4 as an additive led to the formation of 1H-indole-2,3-dicarboxamides, while PivOK facilitated the production of 3-imino-3,4-dihydropyrrolo[3,4-b]indol-1(2H)-ones, achieving moderate to high yields. Control experiments indicated that 3-imino-3,4-dihydropyrrolo[3,4-b]indol-1(2H)-ones could convert into 1H-indole-2,3-dicarboxamides through nucleophilic attack by H2O in the reaction mixture.
The initial screening involved the reaction of 1H-indole-3-carboxamide 1a with tert-butyl isocyanide 2a, using Co(acac)2 as a catalyst and an oxidant in DMSO at 120 °C for 24 hours.