5-Sulfurated Imidazo[1,5-a]Pyridin-3-ylidenes: Ligands for π-Acidic Catalysts

A series of 5-sulfurated imidazo[1,5-a]pyridin-3-ylidenes (Imidazo[1,5-a]pyridine carbenes: IPCs) and their Cu and Pd complexes were synthesized. Theoretical investigations of the free carbenes and Cu complexes implied that the IPCs were good pi-acceptors. Particularly, Cu complexes of 5-arylsulfonyl IPC were strong pi-acids. These complexes were tested as pi-acidic catalysts in the Cu-catalyzed hydroboration of an internal alkyne with diboron and the Mizoroki-Heck reaction. As a result, the trend in reactivity corresponded with the theoretical considerations.

Automated summary

A series of 5-sulfurated imidazo[1,5-a]pyridin-3-ylidenes (IPC) and their Cu and Pd complexes were synthesized and their properties were theoretically investigated. The results showed that these compounds exhibited good pi-acceptor and pi-acidic properties in reactions.