5-Borono-2-chlorobenzoic acid (200 mg, 1 mmol), 3-iodophenylboronic acid (125 mg, 0.5 mmol), K2CO3 (207 mg, 1.5 mmol) and PdCl2(PPh3)2 (37 mg, 0.05 mmol) were dissolved in a mixture of toluene-MeOH (17 mL:1.7 mL) and heated at 75° C. for 3 hours. The mixture was filtered through celite washed with water and the solvent was evaporated in vacuo. The formed crude residue was acidified with 2 M HCl and extracted into EtOAc and dried over anhyd. Na2SO4, evaporated solvent in vacuo to obtain crude 3′-borono-4-chlorobiphenyl-3-carboxylic acid as a reddish brown solid. The crude product was used for the next step without further purification.
