C([Li])CCC.Br[C:7]1[CH:12]=[CH:11][C:10]([CH2:13][CH2:14][CH3:15])=[CH:9][CH:8]=1.[B:16](OC(C)C)([O:21]C(C)C)[O:17]C(C)C.[Cl-].[NH4+]>C1COCC1.O>[CH3:7][CH2:8][CH2:9][CH:10]([CH3:13])[CH3:11].[CH2:13]([C:10]1[CH:11]=[CH:12][C:7]([B:16]([OH:21])[OH:17])=[CH:8][CH:9]=1)[CH2:14][CH3:15]n-Butyl lithium (34 ml of a 1.6M solution in hexanes) was added dropwise to a stirred solution of 1-bromo-4-propylbenzene (9.96 g) in dry THF (30 ml) at -70° C. under argon. The reaction was stirred for 1 hour at -70° C. before addition of triisopropyl borate (12.7 ml) and then stirred for a further 90 minutes at -70° C. before addition of saturated aqueous ammonium chloride solution (30 ml). The reaction was stirred at -70° C. for a further 10 minutes, water (100 ml) was added and the reaction was allowed to warm to ambient temperature. The reaction mixture was extracted with diethyl ether (3×50 ml), the combined organic layers were dried (MgSO4) and then the solvent was removed by evaporation. Trituration of the resultant clear oil with isohexane gave 4-propylphenylboronic acid as a white solid, 6.7 g, mass spectrum (negative electrospray (-ve ESP)): 163 (M-H)-.
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