反应详情

Sodium hydride (60% dispersion in mineral oil, 2.33 g, 58.3 mmol) was washed with hexanes (2×10 mL) in a 100 mL two neck round bottom flask under nitrogen then suspended in DMF (30 mL). The suspension was treated dropwise with ethyl 2-(methylsulfonyl)propanoate (10.0 g, 55.49 mmol) in DMF (10 mL). The mixture was stirred 30 min at RT, cooled to 0° C., and treated drop-wise with 1,2-dibromoethane (5.17 mL, 58.8). The mixture was allowed to warm to room temperature while stirring overnight. The mixture was quenched with saturated aq ammonium chloride (100 mL) and extracted with diethyl ether (4×50 mL). Combined organics were washed with 50% saturated sodium chloride (4×50 mL), dried (MgSO4), and concentrated in vacuo. Crude material was purified via silica chromatography (350 g, 230-400 mesh) and an eluent of EtOAc in hexanes (10-20%) to afford the title compound as a pale yellow oil (7.9 g, 50%). 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1.33 (t, J=7.05 Hz, 3H) 1.64 (s, 3H) 2.49-2.59 (m, 1H) 2.78 (ddd, J=13.89, 10.16, 6.64 Hz, 1H) 3.05 (s, 3H) 3.33-3.41 (m, 1H) 3.46-3.54 (m, 1H) 4.22-4.37 (m, 2H).

1. temperaturecooled to 0° C.
2. temperatureto warm to room temperature
3. stirringwhile stirring overnight
4. customThe mixture was quenched with saturated aq ammonium chloride (100 mL)
5. extractionextracted with diethyl ether (4×50 mL)
6. washCombined organics were washed with 50% saturated sodium chloride (4×50 mL)
7. dry with materialdried (MgSO4)
8. concentrationconcentrated in vacuo
9. customCrude material was purified via silica chromatography (350 g, 230-400 mesh)