Br[C:2]1[CH:7]=[C:6](C(CC)C)[CH:5]=[CH:4][C:3]=1[O:12][CH3:13].[CH2:14]([Li])[CH2:15][CH2:16][CH3:17].[B:19](OC)([O:22]C)[O:20]C.[Cl-].[NH4+]>O1CCCC1.C(OCC)(=O)C>[CH:15]([C:5]1[CH:6]=[CH:7][CH2:2][C:3]([O:12][CH3:13])([B:19]([OH:22])[OH:20])[CH:4]=1)([CH2:16][CH3:17])[CH3:14]
2-Bromo-4-sec-butyl-1-methoxy-benzene (1.15 g) is dissolved in tetrahydrofuran (17 ml) and the mixture is cooled to −78° C., and thereto is added dropwise 1.6M n-butyllithium in hexanes, and the mixture is stirred at −78° C. for 15 minutes. To the reaction solution is added trimethyl borate (1.47 g), and the reaction mixture is stirred at −78° C. for 30 minutes, and thereto are added a saturated aqueous ammonium chloride solution and ethyl acetate. The mixture is separated, and the organic layer is washed with a saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure to give crude 5-sec-butyl-1-methoxy-benzene boronic acid (950 mg). NMR (CDCl3): 0.81 (3H, t), 1.22 (3H, d), 1.58 (2H, m), 2.58 (1H, m), 3.90 (3H, s), 6.25 (2H, s), 6.85 (2H, d), 7.25 (1H, d), 7.65 (1H, s).
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