反应详情

To a suspension of methyltriphenylphosphonium bromide (0.62 g, 1.7 mmol) in tetrahydrofuran (3 mL) at 0° C. was added a solution of 1.0 M potassium t-butoxide in tetrahydrofuran (1.5 mL, 1.5 mmol). The mixture was allowed to warm to room temperature and stirred for 1 h. After which, the solution was cooled to −40° C. and a solution of Example 181A (0.15 g, 0.6 mmol) in tetrahydrofuran (3 mL) was added dropwise. The reaction mixture was stirred at −40° C. for 1 h, and then allowed to warm to room temperature and stirred for 2 h. The solution was quenched with saturated NH4Cl solution (15 mL) and extracted with ethyl acetate (3×10 mL). The combined organic extracts were dried (Na2SO4), filtered and concentrated in vacuo. Column chromatography on silica (hexane) afforded product as a colorless oil (0.13 g, 87%). 1H NMR (300 MHz, CDCl3) δ ppm 0.63 (m, 1 H), 0.77 (dd, J=12.87, 6.62 Hz, 6 H), 0.90 (m, 1 H), 1.40 (m, 1 H), 1.79 (m, 1 H), 2.17 (m, 1 H), 3.50 (d, J=3.68 Hz, 2 H), 3.59 (s, 3 H), 4.99 (m, 3 H), 6.00 (dd, J=17.65, 10.66 Hz, 1 H), 7.16 (m, 4 H).

1. temperatureAfter which, the solution was cooled to −40° C.
2. stirringThe reaction mixture was stirred at −40° C. for 1 h
3. temperatureto warm to room temperature
4. stirringstirred for 2 h
5. customThe solution was quenched with saturated NH4Cl solution (15 mL)
6. extractionextracted with ethyl acetate (3×10 mL)
7. dry with materialThe combined organic extracts were dried (Na2SO4)
8. filtrationfiltered
9. concentrationconcentrated in vacuo