反应详情

A solution of 21 (0.7 g, 2.66 mmol) in anhydrous tetrahydrofuran (15 mL) was stirred under nitrogen at −78° C. and 2.5M n-butyllithium in hexanes (1.1 mL, 2.75 mmol) was added at such a rate that the temperature did not exceed −70° C. Stirring was continued at −78° C. for 1 hr when a solution of 20 (0.8 g, 2.66 mmol) in tetrahydrofuran (5 mL) was added at such a rate that the temperature did not exceed −65° C. Stirring was continued at −78° C. for 30 min., then for 2 hrs at room temperature. The reaction mixture was poured onto 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 crude 22 was used as such in the next step.

1. customdid not exceed −70° C
2. customdid not exceed −65° C
3. stirringStirring
4. waitwas continued at −78° C. for 30 min.
5. waitfor 2 hrs 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