反应详情

A solution of 24.8 g (0.200 moles) dimethyl methyl-phosphonate (Aldrich) in 250 ml dry tetrahydrofuran was cooled to -78° in a dry nitrogen atomsphere. To the stirred phosphonate solution was added 92 ml of 2.38 M n-butyllithium in hexane solution (Alfa Inorganics, Inc.) dropwise over a period of 30 minutes at such a rate that the reaction temperature never rose above -65°. After an additional 5 minutes stirring at -78°, 22.2 g (0.100 mole) methyl 3-(1-adamantyl)propionate was added dropwise at a rate that kept the reaction temperature less than -70° (20 minutes). After 1.0 hour at -78° the reaction mixture was allowed to warm to ambient temperature, neutralized with 55 ml acetic acid and rotary evaporated to a white gel. The gelatenous material was taken up to 50 ml water, the aqueous phase extracted with 100 ml portions of methylene chloride (4X), the combined organic extracts were backwashed with water (4 × 100 ml), dried (MgSO4), and concentrated (water aspirator) to a crude residue and distilled, b.p. 195-200° (<0.02 mm) to give dimethyl 2-oxo-4-(1-adamantyl)butylphosphonate (2b) weighing 36.6 g (100% yield).

1. customthe reaction temperature less than -70° (20 minutes)
2. waitAfter 1.0 hour at -78° the reaction mixture was allowed
3. customrotary evaporated to a white gel
4. extractionthe aqueous phase extracted with 100 ml portions of methylene chloride (4X)
5. dry with materialdried (MgSO4)
6. concentrationconcentrated (water aspirator) to a crude residue
7. distillationdistilled