General procedure for the synthesis of 3-bromo-5-chlorophenol from m-chlorobromobenzene: In an argon-purged flask, (1,5-cyclooctadiene)(methoxy)iridium(I) dimer (84 mg, 0.13 mmol), 4,4'-di-tert-butyl-2,2'-bipyridine (69 mg, 0.26 mmol), and bis(pinacolate)diboron (1.29 g, 5.11 mmol) were added. 5.11 mmol), followed by hexane (26 mL) and 1-bromo-3-chlorobenzene (1 mL, 8.51 mmol) sequentially. The reaction mixture was stirred at room temperature for 18 hours. Upon completion of the reaction, the mixture was concentrated under vacuum and redissolved in acetone (26 mL) followed by addition of an aqueous (26 mL) solution of Oxone (5.23 g, 8.51 mmol) [Note: exothermic phenomena were observed during the reaction].After 10 min, the reaction mixture was diluted with dichloromethane. The organic and aqueous layers were separated and the aqueous layer was extracted with dichloromethane. The organic phases were combined, washed with brine, dried and concentrated in vacuum to give 3-bromo-5-chlorophenol (1.43 g, 81% yield).LCMS (Method 3): retention time 3.74 min, mass-to-charge ratio m/z 205,207 [M-H+].
