[Si:1]([O:8][C:9]1[C:10]([F:18])=[C:11]([CH:15]=[CH:16][CH:17]=1)[C:12]([OH:14])=O)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].S(Cl)(Cl)=O.C([N:25]([CH2:28][CH3:29])CC)C.[OH2:30]>C1(C)C=CC=CC=1.C(Cl)Cl>[Si:1]([O:8][C:9]1[C:10]([F:18])=[C:11]([CH:15]=[CH:16][CH:17]=1)[C:12]([NH:25][CH2:28][C@H:29]([C:9]1[CH:10]=[CH:11][CH:15]=[CH:16][CH:17]=1)[OH:30])=[O:14])([C:4]([CH3:5])([CH3:6])[CH3:7])([CH3:2])[CH3:3]To a solution of 3-tert-butyldimethylsilyloxy-2-fluorobenzoic acid (3.3 g, 12 mmol, example 36B) in toluene (30 ml) was added thionyl chloride (1.3 ml, 18 mmol) carefully at ambient temperature. After addition was complete, the reaction mixture was heated at reflux for 40 min, then cooled and concentrated in vacuo. The residual oil was dissolved in CH2Cl2 (20 ml) and added dropwise to a solution of (+)-2-amino-1(S)-phenylethanol (1.7 g, 12 mmol, see A. I. Meyers and J. Slade. J. Org. Chem. 1980, 45, 2785.) and triethylamine (2.0 ml, 15 mmol) in CH2Cl2 (20 ml) cooled to 0° C. The reaction mixture was allowed to warm to ambient temperature and stirred a further 30 min. The mixture was poured into water (100 ml) and extracted with CH2 Cl2 (3×10 ml). The combined organic extracts were washed with saturated aqueous NaHCO3 (100 ml), dried (MgSO4) and concentrated under reduced pressure. The crude product was purified by column chromatography on silica gel eluting with hexane/ethyl acetate (=3:2) to afford title compound (4.6 g, 97%) as a pale yellow liquid.
Loading…
