反应详情

温度

25 °C

To 60% sodium hydride (336 mg, 10 mmol) in mineral oil) in tetrahydrofuran (20 mL) at 0° C. was added dropwise a solution of 5-vinylpyrrolidin-2-one (1.0 g, 9.0 mmol) in tetrahydrofuran (10 mL) over a 5 minute period. The cooling bath was removed and the solution was allowed to warm to 25° C. to ensure complete anion generation. To the anion at 25° C. was added dropwise a solution of (2S)-2-((1,1-dimethylethyl)dimethylsilyloxy)propanoyl chloride (2.23 g, 10 mmol) in tetrahydrofuran (10 mL) over a 5 minute period. TLC indicated that the reaction was complete upon addition of the acid chloride (silica gel plates; hexane and ethyl acetate, 9:1). The solvent was removed by rotary evaporation affording a thick slug. The slug was dissolved in methylene chloride (75 mL) and washed with water (1×50 mL) and dried (MgSO4). Concentration and purification by flash chromatography on silica gel (EM 60, 0.040-0.063 partical size, 230-400 Mesh, column size: 4.5 cm diameter×15 cm length) using hexane and ethyl acetate (19:1) afforded 1.40 g (47%) of (5S)-N-((2S)-2-((1,1-dimethylethyl)dimethylsilyloxy)propanoyl)-5-ethenylpyrrolidin-2-one (9a) as clear liquid: 1H NMR (CDCl3) δ0.0300 (s,3 H), 0.0656 (s, 3 H), 0.877 (s, 9 H), 1.37 (d, J=6.5 Hz, 3 H), 1.82-1.88 (m, 1 H) 2.21 (p, J=10.7 Hz, 1 H), 2.34-2.47 (m, 1 H), 2.60 (p, J=9.8 Hz, 1 H), 4.88 (br, 1 H), 5.05-5.11 (m, 2 H), 5.36-5.38 (m, 1 H), 5.70-5.79 (m, 1 H); 13C NMR (CDCl3) δ174.86, 174.77, 135.5, 115.4, 66.8, 57.9, 31.6, 25.5, 24.4, 21.1, 18.1, -4.87, -5.16.

1. customThe cooling bath was removed
2. customThe solvent was removed by rotary evaporation
3. customaffording a thick slug
4. washwashed with water (1×50 mL)
5. dry with materialdried (MgSO4)
6. concentrationConcentration and purification by flash chromatography on silica gel (EM 60, 0.040-0.063 partical size, 230-400 Mesh, column size: 4.5 cm diameter×15 cm length)