Iridium(I)-Catalyzed C-H Borylation in Air by Using Mechanochemistry.

Mechanochemistry has been applied for the first time to an iridium(I)-catalyzed C-H borylation reaction. By using either none or just a catalytic amount of a liquid, the mechanochemical C-H borylation of a series of heteroaromatic compounds proceeded in air to afford the corresponding arylboronates in good-to-excellent yields. A one-pot mechanochemical C-H borylation/Suzuki-Miyaura cross-coupling sequence for the direct synthesis of 2-aryl indole derivatives is also described. The present study constitutes an important milestone towards the development of industrially attractive solvent-free C-H bond functionalization processes in air.