Regiospecific ortho‐C−H Allylation of Benzoic Acids

A carboxylate-directed ortho-C−H functionalization has been developed and it allows the regiospecific introduction of allyl residues to benzoic acids. In the presence of a [Ru(p-cymene)Cl2]2 and K3PO4, benzoic acids react with allyl acetates at only 50 °C to give the corresponding ortho-allylbenzoic acids. The protocol is generally applicable to both electron-rich and electron-poor benzoic acids in combination with linear and branched allyl acetates. The products can be further functionalized in situ, for example, by double-bond migration, lactonization, or decarboxylation.