2-Arylation of Indoles using Diaryliodonium Salts

Significance

A new oxidative arylation of indoles using Ar₂IBF₄ salts under mild palladium-catalyzed conditions is described. In the selected group of indoles tested, the tolerance of amine, halogen, methoxy, and nitro groups is demonstrated. Interestingly, both N-unsubstituted and N-Me indoles gave comparable results. Arylating agents bearing both electron-donating and electron-withdrawing as well as sterically hindered substituents gave corresponding indole derivatives in good yields. The reaction was found to be insensitive to air and moisture.

2-Arylation of pyrroles in the range of 70% yield was also demonstrated.