[C:1]([O:11][CH3:12])(=[O:10])[C@H:2]([C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)[OH:3].N1C=CN=C1.[Si:18](Cl)([C:21]([CH3:24])([CH3:23])[CH3:22])([CH3:20])[CH3:19]>ClCCl.CN(C)C1C=CN=CC=1.CCOCC>[CH3:12][O:11][C:1](=[O:10])[CH:2]([O:3][Si:18]([C:21]([CH3:24])([CH3:23])[CH3:22])([CH3:20])[CH3:19])[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1To a solution of commercially available methyl (S)-mandelate (2.39 g, 14.4 mmol) in dichloromethane (50 mL) is added imidazole (1.18 g, 17.3 mmol), tert-butyldimethylsilyl chloride (2.38 g, 15.8 mmol) and 4-dimethylaminopyridine (176 mg, 1.44 mmol). The mixture is stirred for 16 hrs then diluted with ether, washed with water, brine, then dried (MgSO4), filtered and concentrated. The residue is purified by chromatography on silica gel; elution with EtOAc:heptane (25:75) gives 3.67 g of the product. 1H NMR (CDCl3) δ 7.45-7.40 (m, 2H), 7.35-7.25 (m, 3H), 5.20 (s, 1H), 3.65 (s, 3H), 0.90 (s, 9H), 0.10 (s, 3H), 0.05 (s, 3H); MS: m/z 281 (M++1)
Wird geladen…
