Heterogeneous catalytic approaches in C–H activation reactions

Despite the undisputed advances and progress in metal-catalyzed C-H functionalizations, this atom-economical approach had thus far largely been developed with the aid of various metal catalysts that were operative in a homogeneous fashion. While thereby major progress was accomplished, these catalytic systems featured notable disadvantages, such as low catalyst recyclability. This review summarizes the development of user-friendly, recyclable and easily separable heterogeneous catalysts for C-H activation. This strategy was characterized by a remarkably broad substrate scope, considerable levels of chemo-and site-selectivities and proved applicable to C-C as well as C-heteroatom formation processes. Thus, recyclable catalysts were established for arylations, hydroarylations, alkenylations, acylations, nitrogenations, oxygenations, or halogenations, among others. The rapid recent progress in selective heterogeneous C-H functionalizations during the last decade until December 2015 is reviewed.