反应详情

To an acetonitrile solution of methyl 2-(dibenzylamino)-3-hydroxypropanoate (23 g, 76.8 mmol) and sodium sulfate (3.9 g, 27.4 mmol) at 40° C., difluoro(fluorosulfonyl)acetic acid (25 g, 140 mmol) was added dropwise for 1.5 hrs. The reaction mixture was concentrated to dryness and the residue mixed with silica gel in ethyl acetate, then again concentrated to dryness. The product was purified by column chromatography, eluting with 3-4% ethyl acetate in hexanes, to give methyl 2-dibenzylamino-3-difluoromethoxy-propionate (1.3 g, 4.8%) as a colorless oil. 1H NMR (300 MHz, CDCl3): δ(ppm) 7.20-7.40 (m, 10H), 6.18 (bt, 1H), 4.05-4.24 (m, 2H), 3.90 (d, 2H), 3.83 (s, 3H) and 3.64-3.71 (m, 3H).

1. concentrationThe reaction mixture was concentrated to dryness
2. additionthe residue mixed with silica gel in ethyl acetate
3. concentrationagain concentrated to dryness
4. customThe product was purified by column chromatography
5. washeluting with 3-4% ethyl acetate in hexanes