反应详情

A solution of 20.4 g (164 mmoles) dimethyl methylphosphonate (Aldrich) in 200 ml dry tetrahydrofuran was cooled to -78° in a dry nitrogen atmosphere. To the stirred phosphonate solution was added 82.6 ml of 2.25M n-butyllithium in hexane solution (Alfa Inorganics, Inc.) dropwise over a period of 20 minutes at such a rate that the reaction temperature never rose above -65°. After an additional 5 minutes stirring at -78°, 14.0 g (73.5 mmole) methyl indane-2-carboxylate 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 20 ml acetic acid and rotary evaporated to a white gel. The gelatinous material was taken up in 50 ml water, the aqueous phase extracted with 75 ml portions of methylene chloride (4x), the combined organic extracts were backwashed (75 ml H2O), dried (MgSO4), and concentrated (water aspirator) to a crude residue and distilled, b.p. 150°-160° (0.1 mm) to give 17.0 g (86.4%) dimethyl 2-oxo-2-(2-indany)ethylphsphonate (2i).

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 75 ml portions of methylene chloride (4x)
5. dry with materialdried (MgSO4)
6. concentrationconcentrated (water aspirator) to a crude residue
7. distillationdistilled