C([Li])(C)(C)C.[C:6]([C:10]1[CH:15]=[CH:14][C:13]([O:16][CH2:17][O:18][CH3:19])=[CH:12][CH:11]=1)([CH3:9])([CH3:8])[CH3:7].[B:20](OC)([O:23]C)[O:21]C>CCCCC>[C:6]([C:10]1[CH:15]=[CH:14][C:13]([O:16][CH2:17][O:18][CH3:19])=[C:12]([B:20]([OH:23])[OH:21])[CH:11]=1)([CH3:9])([CH3:7])[CH3:8]Following a procedure by Ronald, R. C. et al (J. Org. Chem., 1980, 40, 2224-2229) a 1.7 molar solution of tert-butyl lithium in pentane (6.70 mL, 11.3 mmol) was added to a solution of 1-(tert-butyl)-4-(methoxymethoxy)benzene (2.00 g, 10.3 mmol, Kovacs, M. S. et al J. Chem. Soc. Dalton, 2001, 3015-3024) in pentane (40 mL) under a nitrogen atmosphere at 0° C. A solid precipitated and the pentane was evaporated under a steady stream of nitrogen gas. To this remaining solid was added tetrahydrofuran (50 mL) and the solution was cooled to −78° C. Trimethyl borate (1.70 mL, 15.5 mmol) was added slowly and the solution was stirred at −78° C. under nitrogen gas for 30 minutes. Thin layer chromatography showed consumption of the starting material and water (10 mL) was added and the solution was partitioned between ethyl acetate and 1 N aqueous sodium hydroxide solution. The organic phase was separated and dried with sodium sulfate, filtered and concentrated under reduced pressure to give 2.70 g of crude (5-(tert-butyl)-2-(methoxymethoxy)phenyl)boronic acid which was used without further purification.
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