[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([CH3:8])=[CH:4][C:3]=1[OH:9].C(N(CC)CC)C.[C:17]([Si:21](Cl)([CH3:23])[CH3:22])([CH3:20])([CH3:19])[CH3:18]>CN(C1C=CN=CC=1)C.CN(C=O)C.CCOCC>[C:17]([Si:21]([O:9][C:3]1[CH:4]=[C:5]([CH3:8])[CH:6]=[CH:7][C:2]=1[Cl:1])([CH3:23])[CH3:22])([CH3:20])([CH3:19])[CH3:18]A solution containing 2-chloro-5-methylphenol 79 (3.50 g, 25 mmol), triethylamine (3.8 mL, 27 mmol), and DMAP (0.030 g, 0.25 mmol) in 50 mL of DMF was chilled to 0° C. under N2. A solution of tert-butylchlorodimethylsilane (3.9 g, 26 mmol) in 5 mL of DMF was added to the reaction mixture slowly via syringe over 5 min. The reaction was warmed to room temperature and stirred for 12 h. The mixture was diluted with ether and it was extracted with 2×1 N HCl, water, and then brine. The organic layer was dried over MgSO4, filtered, and concentrated in vacuo. The crude material was purified by silica gel chromatography using a 5% to 30% gradient of EtOAc in hexanes as the eluant. The desired fractions were combined and concentrated to give tert-butyl(2-chloro-5-methylphenoxy)dimethylsilane 80 (6.15 g, 98% yield) as a colorless oil.
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