反应详情

A solution of 2-(benzyloxycarbonylamino)-2-(ethoxycarbonyl)hex-5-enoic acid (1.54 g, 4.6 mmol) and triethylamine (557 mg, 5.52 mmol, 0.76 mL) in tetrahydrofuran (10 mL) was cooled to −30° C. and treated with ethyl chloroformate (522 mg, 4.82 mmol, 0.46 mL) and stirred for 30 minutes. A solution of sodium borohydride (175 mg, 4.6 mmol) in water (2 mL) was added and the mixture was stirred for 30 minutes. Once the reaction was complete, 3 N hydrochloric acid (1 mL) was added and the mixture was diluted with ethyl acetate (50 mL), washed with water (1×50 mL) and extracted with ethyl acetate (1×50 mL). The combined organic layers were concentrated and purified using a combiflash system (2×12 g silica gel column, eluting with 10-50% ethyl acetate in heptanes) to give ethyl 2-(benzyloxycarbonylamino)-2-(hydroxymethyl)hex-5-enoate (700 mg, 48%). 1H NMR (CDCl3) δ 7.29 (m, 5H), 5.82 (bs, 1H), 5.68-5.62 (m, 1H), 5.03 (s, 1H), 4.94-4.86 (m, 2H), 4.17 (m, 2H) 3.76 (dd, J=11.4 Hz, 1H), 1.97 (m, 2H), 1.77 (m, 2H), 1.21 (t, J=7.2 Hz, 3H). MS found for C17H23NO5 m/z [322 (M+1)].

1. stirringthe mixture was stirred for 30 minutes
2. washwashed with water (1×50 mL)
3. extractionextracted with ethyl acetate (1×50 mL)
4. concentrationThe combined organic layers were concentrated
5. custompurified
6. washa combiflash system (2×12 g silica gel column, eluting with 10-50% ethyl acetate in heptanes)