Br[C:2]1[CH:3]=[C:4]([CH3:13])[C:5]2[O:9][CH2:8][C:7]([CH3:11])([CH3:10])[C:6]=2[CH:12]=1.C([Li])(C)(C)C.CCCCC.[B:24](OC)([O:27]C)[O:25]C>O1CCCC1>[CH3:10][C:7]1([CH3:11])[C:6]2[CH:12]=[C:2]([B:24]([OH:27])[OH:25])[CH:3]=[C:4]([CH3:13])[C:5]=2[O:9][CH2:8]1Following General Procedure A and using 5-bromo-3,3,7-trimethyl-2,3-dihydro-benzofuran (1.2 g, 5 mmol), 12 mL of anhydrous tetrahydrofuran, 1.7M solution of t-butyllithium in n-pentane (6.17 mL, 10.5 mmol) and trimethyl borate (1.2 mL, 10.5 mmol) the title compound was obtained as a foam that was used as such for the next step without purification and characterization. 5-Bromo-3,3,7-trimethyl-2,3-dihydro-benzofuran can be prepared as described in U.S. Pat. No. 6,093,838, incorporated herein by reference.
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