Table 3.

Ligand enabled C(sp²)─H hydroxylation of benzoic acids^a

^aConditions A: Carboxylic acid 3 (1 mmol), Pd(OAc)₂ (2 mol%), L4 (4 mol%), H₂O₂ (35% aqueous solution, 3.5 equiv.), and K₂HPO₄•3H₂O (1.5 equiv.) in CH₃CN (3.0 mL), r.t. 24 h.; Conditions B: Carboxylic acid 3 (1 mmol), Pd(OAc)₂ (5 mol%), 14 (10 mol%), H₂O₂ (35% aqueous solution, 3.5 equiv.), and CsOAc (1.5 equiv.) in DMA (3.0 mL), 60 °C. 24 h. Isolated yields.

^b60 °C

^cK₂HPO₄•3H₂O instead of CsOAc, 48h.

^d0.5 mmol scale, r.t.