[C:1]([O:5][C:6](=[O:35])[CH2:7][CH2:8][C:9]1[CH:14]=[CH:13][C:12]([O:15][Si:16]([C:29]([CH3:32])([CH3:31])[CH3:30])([C:23]2[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=2)[C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)=[CH:11][C:10]=1[CH2:33]O)([CH3:4])([CH3:3])[CH3:2].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C(Br)(Br)(Br)[Br:56]>C1COCC1>[C:1]([O:5][C:6](=[O:35])[CH2:7][CH2:8][C:9]1[CH:14]=[CH:13][C:12]([O:15][Si:16]([C:29]([CH3:32])([CH3:31])[CH3:30])([C:23]2[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=2)[C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)=[CH:11][C:10]=1[CH2:33][Br:56])([CH3:4])([CH3:3])[CH3:2]A 200 mL round bottomed flask was charged with 3-[4-(tert-butyldiphenylsilanyloxy)-2-hydroxymethylphenyl]propionic acid tert-butyl ester (3.03 g, 6.18 mmol), anhydrous THF (75 mL), and then triphenylphosphine (3.24 g, 12.4 mmol) and CBr4 (4.10 g, 12.4 mmol). The yellow mixture was stirred at ambient temperature under a nitrogen atmosphere for 1 h and was concentrated. The residue was diluted with EtOAc (500 mL). The organic layer was washed with brine (2×), dried (Na2SO4), and concentrated to a solid. The crude product was purified using a Biotage medium pressure chromatography system (EtOAc:hexanes 10:90) to give a yellow oil (2.95 g, 86%), MS (ES) m/e 572 (M+NH4).
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