反应详情

A solution of 25 g (0.21 mole) dimethyl methylphosphonate (Aldrich) in 300 ml dry tetrahydrofuran was cooled to -78° in a dry nitrogen atmosphere. To the stirred phosphonate solution was added 80 ml of 2.67 M n-butyllithium in hexane solution (Alfa Inorganics, Inc.) dropwise over a period of 18 minutes at such a rate that the reaction temperature never rose above -65°. After an additional 5 minutes stirring at -78°, 16.0 g (0.104 mole) methyl 3-(2-furyl) propionate was added dropwise at a rate that kept the reaction temperature less than -70° (20 minutes). After 3.5 hours at -78° the reaction mixture was allowed to warm to ambient temperature, neutralized with 6 ml acetic acid and rotary evaporated to a white gel. The gelatinous material was taken up in 75 ml water, the aqueous phase extracted with 100 ml portions of chloroform (3×), the combined organic extracts were backwashed (50 cc H2O), dried (MgSO4), and concentrated (water aspirator) to a crude residue and distilled, b.p. 148°-50° (0.5 mm) to give 8.4 g dimethyl 2-oxo-4-(2-furyl)butylphosphonate (2C).

1. customthe reaction temperature less than -70° (20 minutes)
2. waitAfter 3.5 hours at -78° the reaction mixture was allowed
3. customrotary evaporated to a white gel
4. extractionthe aqueous phase extracted with 100 ml portions of chloroform (3×)
5. dry with materialdried (MgSO4)
6. concentrationconcentrated (water aspirator) to a crude residue
7. distillationdistilled