Br[C:2]1[CH:15]=[CH:14][C:5]([O:6][Si:7]([C:10]([CH3:13])([CH3:12])[CH3:11])([CH3:9])[CH3:8])=[CH:4][C:3]=1[CH:16]([CH3:18])[CH3:17].C([Li])(C)(C)C.CN([CH:27]=[O:28])C>CCCCC.O>[C:10]([Si:7]([CH3:9])([CH3:8])[O:6][C:5]1[CH:14]=[CH:15][C:2]([CH:27]=[O:28])=[C:3]([CH:16]([CH3:18])[CH3:17])[CH:4]=1)([CH3:13])([CH3:12])[CH3:11]A solution of (4-bromo-3-isopropyl-phenoxy)-tert-butyl-dimethyl-silane (Intermediate 145, 1.03 g, 3.13 mmols) in 25 mL E2O was cooled to −78° C. and treated with tert-butyllithium (401.0 mg, 6.26 mmols; 3.7 mL of a 1.7M solution in pentane). After 30 minutes the reaction was quenched with DMF (913.0 mg, 12.5 mmols) and warmed to room temperature. The solution was diluted with H2O, extracted with Et2O and the combined organic layers washed with H2O and saturated aqueous NaCl before being dried (MgSO4) and concentrated under reduced pressure. Column chromatography (2% EtOAc-hexanes) afforded 480.0 mg (55%) of the title compound as a colorless oil.
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