Carboxy Group as a Remote and Selective Chelating Group for C-H Activation of Arenes.

The first example of carboxy group assisted, remote-selective C(sp2 )-H activation with a PdII catalyst has been developed and proceeds through a possible κ2 coordination of the carboxy group, thus suppressing the ortho-C-H activation through κ1 coordination. Besides meta-C-H olefination, direct meta-arylation of hydrocinnamic acid derivatives with low-cost aryl iodides has been achieved for the first time. These findings may motivate the exploration of novel reactivities of the carboxy assisted C-H activation reactions with intriguing selectivities.