反应详情

A solution of methyltriphenylphosphoniumbromide (1.4 g, 3.9 mmol) in anhydrous tetrahydrofuran (15 mL) was stirred under nitrogen on an ice bath and 2.5 M n-butyllithium in hexanes (1.5 mL, 3.75 mmol) was slowly added. After 20 min. the cold bath was removed and stirring was continued at room temperature for 1 hr. The reaction mixture was cooled on an ice bath and a solution of 11 (0.82 g, 1.95 mmol) in tetrahydrofuran (15 mL) was added at such a rate that the temperature did not exceed 5° C. Stirring was continued overnight at room temperature. The reaction mixture was poured on saturated ammonium chloride (120 mL) and extracted with ethyl acetate (150 mL). The organic extract was washed with water (2×80 mL), dried over sodium sulfate and stripped. The residue was purified by chromatography on silica (50 g) with 5% ethyl acetate in heptane (3 L) to produce pure 12 (0.13 g, 16%).

1. customAfter 20 min. the cold bath was removed
2. temperatureThe reaction mixture was cooled on an ice bath
3. customdid not exceed 5° C
4. stirringStirring
5. waitwas continued overnight at room temperature
6. extractionextracted with ethyl acetate (150 mL)
7. extractionThe organic extract
8. washwas washed with water (2×80 mL)
9. dry with materialdried over sodium sulfate
10. customThe residue was purified by chromatography on silica (50 g) with 5% ethyl acetate in heptane (3 L)