Regioselective C−H Alkylation via Carboxylate‐Directed Hydroarylation in Water

Abstract In the presence of catalytic [RuCl 2 ( p ‐cym)] 2 and using Li 3 PO 4 as the base, benzoic acids react with olefins in water to afford the corresponding 2‐alkylbenzoic acids in moderate to excellent yields. This C−H alkylation process is generally applicable to diversely substituted electron‐rich and electron‐deficient benzoic acids, along with α,β‐unsaturated olefins including unprotected acrylic acid. The widely available carboxylate directing group can be removed or utilized for further derivatization. Mechanistic investigations revealed that the transformation proceeds via a ruthenacycle intermediate.