CID 406 → HCID 21321719, compound

Participants

Reaction Steps

A solution of 49.6 g (0.40 mole) dimethyl methylphosphonate (Aldrich) in 500 ml dry tetrahydrofuran is cooled to -78° in a dry nitrogen atmosphere. To the stirred phosphonate solution is added 188 ml of 2.34 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 rises above -65°. After an additional 5 minutes stirring at -78°,25.6 g (0.20 mole) methyl 5-cyclopropylvalerate is added dropwise at a rate that keeps the reaction temperature less than -70° (20 minutes). After 1.0 hour at -78° the reaction mixture is allowed to warm to ambient temperature, neutralized with 25 ml acetic acid and rotary evaporated to a white gel. The gelatinous material is taken up in 75 ml water, the aqueous phase extracted with 100 ml portions of chloroform (3x), the cmbined organic extracts are backwashed (50 cc H2O), dried (MgSO4), and concentrated (water aspirator) to a crude residue and distilled to give dimethyl 2-oxo-6-cyclopropylhexylphosphonate.

Provenance & Evidence