[CH2:1]([O:8][C:9]1[C:10]([CH2:18][CH3:19])=[CH:11][C:12](Br)=[C:13]([O:15][CH3:16])[CH:14]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C([Li])CCC.CCOCC.[B:30](OCC)([O:34]CC)[O:31]CC>O1CCCC1.C(COC)OC>[CH2:1]([O:8][C:9]1[C:10]([CH2:18][CH3:19])=[CH:11][C:12]([B:30]([OH:34])[OH:31])=[C:13]([O:15][CH3:16])[CH:14]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1The resulting 5-benzyloxy-2-bromo-4-ethyl-1-methoxybenzene (4) is allowed to react with n-butyl lithium in a polar solvent such as ether, glyme or tetrahydrofuran (THF), preferably THF, at a temperature of about −78° C. Triethyl borate is then added to the reaction mixture, and the reaction mixture is allowed to stir at a temperature of about −78° C. The reaction mixture is then allowed to warm to about room temperature. The reaction yields 4-benzyloxy-5-ethyl-2-methoxy-phenylboronic acid (5).
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