反応 #346262

反応方程式

methyl phenylacetate

phosphonate

n-butyllithium

dimethyl methylphosphonate

→

dimethyl 2-oxo-3-phenylpropylphosphonate

収率 29.0%

Dimethyl 2-oxo-3-phenylpropylphosphonate

収率 29.0%

溶媒

acetic acid

hexane

tetrahydrofuran

反応条件

後処理

1. 1
   その他the reaction temperature less than -70° (20 minutes)
2. 2
   workup.WAITAfter 3.5 hours at -78°
3. 3
   その他rotary evaporated (water aspirator) to a white gel
4. 4
   抽出the aqueous phase extracted with 100 ml portions of chloroform (3×)
5. 5
   乾燥dried (MgSO4)
6. 6
   濃縮concentrated (water aspirator) to a crude residue
7. 7
   workup.DISTILLATIONdistilled

実験手順

A solution of 6.2 g (50 mmoles) dimethyl methylphosphonate (Aldrich) in 125 ml dry tetrahydrofuran was cooled to -78° in a dry nitrogen atmosphere. To the stirred phosphonate solution was added 21 ml of 2.37 M n-butyllithium in hexane solution (Alfa Inorganics, Inc.) dropwise over a period of 18 minutes at such a rate that the reduction temperature never rose above -65°. After an additional 5 minutes stirring at -78°, 7.5 g (50.0 mmole) methyl phenylacetate 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 (water aspirator) 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. 134°-5° (<0.1 mm) to give 3.5 g (29% dimethyl 2-oxo-3-phenylpropylphosphonate (2a).

出典