Ruthenium-Catalyzed C-H Benzoxylation of tert-Benzamides with Aromatic Acids by Weak Coordination.

A highly regioselective C-H benzoxylation of tertiary benzamides with aromatic acids by weak O-amide coordination in the presence of [{RuCl2(p-cymene)}2], AgSbF6, and (NH4)2S2O8 in 1,2-dichloroethane at 100 °C for 24 h to afford ortho-benzoxylated tertiary benzamides is described. Selectively, ortho-benzoxylated cyclic benzamides were converted into ortho-benzoxylated benzaldehydes by using Cp2ZrHCl at room temperature. Subsequently, substituted salicylic acids were prepared by deprotection of the ester and amide groups of ortho-benzoxylated cyclic benzamides.