反应详情

To a solution of (R)-N-allyloxyalanine benzyl ester (2a) (2.59 g, 11 mmol) and Et3N (1.11 g, 11 mmol) in dry CH2Cl2 (30 mL), a solution of bromoacetyl bromide (2.22 g, 11 mmol) in dry CH2Cl2 (20 mL) was added dropwise with cooling (−25˜−30° C.) and stirring. The reaction mixture was stirred for 1 h at 0˜+5° C. and allowed to warm up to RT. After dilution with CH2Cl2 (ca. 30 mL), the mixture was washed with water (2×30 mL), 1N HCl (30 mL), sat. aq. NaHCO3 (30 mL), and dried over MgSO4. Removal of the solvent afforded 3.90 g (99%) of the product 3 as a yellowish oil. 1H NMR (100 MHz) in CDCl3 (J, Hz): δ 1.60 (3H, d, 3J=7.3, MeCH), 4.08 (2H, CH2Br), 4.49 (2H, dt, 3J=6.1, 4J=0.9, OCH2CH═CH2), 4.98 (1H, q, MeCH, 3J=7.3), 5.16-5.48 (2H, m, CH═CH2), 5.20 (2H, CH2Ph), 5.76-6.15 (1H, m, 3J=6.1, 3Jcis=10.0, 3Jtrans=17.3, CH═CH2), 7.29-7.41 (5H, m, Ph). IR (film), cm−1: 1746, 1678, 1455, 1214. MS (CI, isobutane), m/Z: 357 (M++1), 356 (M+).

1. temperaturewith cooling (−25˜−30° C.)
2. stirringThe reaction mixture was stirred for 1 h at 0˜+5° C.
3. washAfter dilution with CH2Cl2 (ca. 30 mL), the mixture was washed with water (2×30 mL), 1N HCl (30 mL), sat. aq. NaHCO3 (30 mL)
4. dry with materialdried over MgSO4
5. customRemoval of the solvent