Direct CH Bond Arylation of Indoles with Aryl Boronic Acids Catalyzed by Palladium Nanoparticles Encapsulated in Mesoporous Metal-Organic Framework

Highly dispersed Pd nanoparticles encapsulated in the mesoporous metal-organic framework MIL-101 demonstrated high activity and selectivity for the direct C2 arylation of various indoles with aryl boronic acids using O2 or 2,2,6,6-tetramethylpiperidine N-oxyradical as an external oxidant in acidic media under mild conditions. The green catalyst is easily recoverable and can be reused six times without leaching and loss of activity.