Site-Selective Aerobic C-H Monoacylation of Carbazoles Using Palladium Catalysis

This manuscript describes the development of a remarkably general palladium-catalyzed monoacylation of carbazoles using toluene derivatives playing the dual role of acyl source and organic solvent. The method uses NHPI as the cocatalyst and oxygen as the sole oxidant. Interestingly, the acylation of monosubstituted N-pyridylcarbazoles takes place regioselectively at the C-8 position. The scope of the method is explored using aldehyde as the acyl source. This highly site-selective acylation proceeds through a radical process.

Automated summary

This study presents a general palladium-catalyzed monoacylation method for carbazoles, using toluene derivatives as both acyl source and organic solvent, with NHPI and oxygen as cocatalyst and sole oxidant, respectively. The regioselective acylation at C-8 position of monosubstituted N-pyridylcarbazoles is achieved using aldehyde as the acyl source, indicating a highly site-selective acylation proceeding through a radical process.