C([Li])CCC.Br[C:7]1[CH:12]=[CH:11][C:10]([S:13]([CH:16]2[CH2:18][CH2:17]2)(=[O:15])=[O:14])=[C:9]([Cl:19])[CH:8]=1.[B:20](OC(C)C)([O:25]C(C)C)[O:21]C(C)C.Cl>O1CCCC1>[Cl:19][C:9]1[CH:8]=[C:7]([B:20]([OH:25])[OH:21])[CH:12]=[CH:11][C:10]=1[S:13]([CH:16]1[CH2:18][CH2:17]1)(=[O:15])=[O:14]n-Butyllithium (1.6 M solution in hexane, 9.2 mL) was added dropwise to a solution of 4-bromo-2-chloro-1-(cyclopropylsulfonyl)benzene obtained in Reference Example 5-30 (1.45 g) and triisopropyl borate (5.54 g) in tetrahydrofuran (15 mL) under cooling at an external temperature of −78° C. in a nitrogen atmosphere, after which the mixture was stirred at the same temperature for three hours. 1 M hydrochloric acid (10 mL) was added and the reaction solution, still basic, was extracted with chloroform. The aqueous layer was made acidic with 1 M hydrochloric acid (10 mL), followed by extraction with chloroform. The solvent was evaporated from the organic layer under reduced pressure to give a crude product of 3-chloro-4-(cyclopropylsulfonyl)phenylboronic acid (1.02 g).
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