反应详情

To a solution of diisopropylamine (9.5 mL, 67.2 mmol) in tetrahydrofuran (100 ml) was added butyllithium (42 mL, 1.6M in hexanes, 67.2 mmol) drop wise at −78° C. and stirred for 30 min. Thus obtained lithium diisopropylamide solution was immediately added by cannulation to a solution of Example 3C (7.36 g, 22.4 mmol) in tetrahydrofuran (100 ml) at −78° C. and stirred for 30 min at the same temperature. Then, dry acetone (8.2 ml, 112 mmol, Acros) was added slowly and the reaction mixture was removed from the cold bath and allowed to warm to room temperature with continued stirring overnight. The reaction mixture was quenched with saturated aqueous NH4Cl solution (100 mL) and the aqueous layer was extracted with ethyl acetate (3×100 mL). The combined organic extracts were dried (Na2SO4), filtered and concentrated. The residue was purified by column chromatography using an Analogix® IT280™ (SiO2, 0-100% ethyl acetate in hexanes) to afford 4.6 g (53%) of the title compound. MS (ESI+) m/z 387 (M+H)+

1. stirringstirred for 30 min at the same temperature
2. customthe reaction mixture was removed from the cold bath
3. stirringwith continued stirring overnight
4. customThe reaction mixture was quenched with saturated aqueous NH4Cl solution (100 mL)
5. extractionthe aqueous layer was extracted with ethyl acetate (3×100 mL)
6. dry with materialThe combined organic extracts were dried (Na2SO4)
7. filtrationfiltered
8. concentrationconcentrated
9. customThe residue was purified by column chromatography