Cl([O-])(=O)(=O)=O.[Mg+2].Cl([O-])(=O)(=O)=[O:8].[O:12]1[CH2:14][C@H:13]1[C:15]([O:17][CH3:18])=[O:16].[CH3:19][O:20][CH2:21][C@@H:22](O)[CH3:23].N1C=CN=C1.[C:30]([Si:34](Cl)([CH3:36])[CH3:35])([CH3:33])([CH3:32])[CH3:31]>CN(C=O)C>[Si:34]([O:8][C@@H:13]([CH2:14][O:12][C@@H:22]([CH3:23])[CH2:21][O:20][CH3:19])[C:15]([O:17][CH3:18])=[O:16])([C:30]([CH3:33])([CH3:32])[CH3:31])([CH3:36])[CH3:35]Magnesium perchlorate (2.79 g, 12.49 mmol) was added in one portion to (S)-methyl oxirane-2-carboxylate (CAS no. 118712-39-3) (5.1 g, 49.96 mmol) and (S)-1-methoxypropan-2-ol (CAS no. 26550-55-0) (4.50 g, 49.96 mmol) at ambient temperature. The resulting suspension was stirred at 50° C. for 16 hours. The reaction mixture was diluted with DMF (50 mL) before adding 1H-imidazole (6.80 g, 99.92 mmol) and tert-butylchlorodimethylsilane (9.04 g, 59.95 mmol). The resulting solution was stirred at 40° C. for 5 hours. The reaction mixture was evaporated to dryness and re-dissolved in ethyl acetate (125 mL), and washed sequentially with water (50 mL) and saturated brine (25 mL). The organic layer was dried (MgSO4) and evaporated. The crude product was purified by flash silica chromatography, eluting with 0 to 50% ethyl acetate in isohexane to afford the product (4.52 g, 30%). 1H NMR (400 MHz, DMSO) δ 0.00 (d, 6H), 0.82 (s, 9H), 0.98 (d, 3H), 3.13-3.28 (m, 5H), 3.50-3.64 (m, 6H), 4.26-4.32 (m, 1H); m/z (ESI+) (M+H)+=307.19; HPLC tR=10.82 min.
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