[C:1]([N@@:4]1[CH2:6][CH:5]1[C:7]([O:9][CH3:10])=[O:8])(=[O:3])[CH3:2].[CH2:11]([OH:14])[C:12]#[CH:13].B(F)(F)F.CCOCC>C(Cl)Cl>[C:1]([NH:4][C@H:5]([CH2:6][O:14][CH2:11][C:12]#[CH:13])[C:7]([O:9][CH3:10])=[O:8])(=[O:3])[CH3:2](R)-Methyl 1-acetylaziridine-2-carboxylate (1.50 g, 10.49 mmol) was dissolved in CH2Cl2 (40 mL) and cooled to −20° C. under Ar, and then propargyl alcohol (0.92 mL, 15.74 mmol) was added. After the solution was stirred (2 min), BF3.Et2O (1.39 mL, 11.01 mmol) was added dropwise. The reaction mixture was allowed to stir at room temperature (2-3 h) and then washed with saturated aqueous NaHCO3 (30 mL) and saturated aqueous brine (30 mL). The organic layer was dried (Na2SO4) and evaporated in vacuo, and then the crude product was purified by column chromatography (SiO2; 3/1 EtOAc/hexanes) and crystallized (cold hexanes) to yield 1.43 g (68%) of desired product as a white solid: mp 58.5-59.5° C.; [α]25D −64.6° (c 1, CHCl3); Rf=0.35 (3/1 EtOAc/hexanes); IR (nujol mull) 3301, 2919, 2114, 1750, 1639, 1542, 1457 cm−1; 1H NMR (CDCl3) δ 2.06 (s, CH3C(O)), 2.46 (t, J=2.3 Hz, CH2CCH), 3.78 (s, OCH3), 3.79 (dd, J=3.3, 9.6 Hz, CHH′OCH2), 3.98 (dd, J=2.9, 9.6 Hz, CHH′OCH2), 4.09-4.21 (m, OCH2C), 4.77-4.82 (m, CH), 6.33-6.35 (br d, J=7.2 Hz, NHCH); 13C NMR (CDCl3) δ 23.3 (CH3C(O)), 52.6 (CH), 52.8 (OCH3), 58.7 (CH2CCH), 69.6 (CH2OCH2), 75.3 (CH2CCH), 79.0 (CH2CCH), 170.1, 170.8 (2 C(O)); HRMS (ESI) 200.0916 [M+H+] (calcd. for C9H14NO4 200.0923); Anal. (C9H13NO4) Calcd.: C, 54.26%; H, 6.58%; N, 7.03%. Found: C, 54.30%; H, 6.66%; N, 6.89%.
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