Mechanochemical Cobalt-Catalyzed C-H Bond Functionalizations by Ball Milling

Ball milling techniques have been applied in the development of a mechanosynthesis of [Cp*Co(CO)I-2], which proved highly efficient as catalyst in mechanochemical C-H bond amidations of indoles in a mixer ball mill. A wide range of amidated products is obtained in excellent yields. Compared to the solution-based methods, the procedure opens a more feasible and environmentally-friendly access to both the cobalt(III) catalyst and 2-amidated indoles.