Palladium-Catalyzed Regiodivergent C-H Olefination of Imidazo[1,2a]pyridine Carboxamide and Unactivated Alkenes

Despite remarkable successes in linear and branched vinyl (hetero) arene synthesis, regiodivergent C-H olefination with a single catalytic system has remained underdeveloped. Overcoming this limitation, a Pd/MPAA-catalyzed regiodivergent C-H olefination of imidazo[1,2a] pyridine carboxamides with unactivated terminal alkenes to generate branched and linear olefinated products depending upon the electronic nature of alkenes is reported herein. Moreover, this protocol can be applied for C-H deuteriation of the corresponding heteroarenes with D2O as deuterium source. Preliminary experimental studies combined with computational investigations (DFT studies) suggest that regiodivergent olefination can be controlled by olefin insertion and beta-hydride elimination steps. A new method for regiodivergent C-H olefination of Imidazo [1,2a] pyridine carboxamide and unactivated alkenes has been developed. This protocol works for a diverse range of Imidazo [1,2a] pyridine carboxamide derivatives and various aliphatic alkenes and styrenes. The success of this chemistry is supported by experimental and computational mechanistic studies, making it a promising solution for a long-standing synthetic challenge in organic chemistry.image

Automated summary

A controlled method for regiodivergent C-H olefination of Imidazo[1,2a] pyridine carboxamide and unactivated alkenes has been developed using Pd/MPAA catalyst. This method can generate branched or linear olefinated products depending on the electronic nature of the alkenes, and can also be applied for C-H deuteriation of heteroarenes.