Reaktion #5281

Reaktionsgleichung

benzyl bromide

ethyl 2-cyanoethyl(diethoxymethyl)phosphinate

ammonium chloride

diisopropylamine

n-butyllithium

→

ethyl 2-benzyl-2-cyanoethyl(diethoxymethyl)phosphinate

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

tetrahydrofuran

hexane

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONis introduced
2. 2
   workup.ADDITIONis added
3. 3
   ExtraktionThe aqueous layer is then extracted with 2×25 ml of diethyl ether
4. 4
   Trocknendried over magnesium sulphate
5. 5
   SonstigeThe solvent is then evaporated under reduced pressure
6. 6
   Sonstigethe crude product chromatographed on silica gel

Vorschrift

To a solution of 0.97 g of diisopropylamine in 40 ml of tetrahydrofuran at -78° C. under an atmosphere of nitrogen are added 6.0 ml of a 1.6M solution of n-butyllithium in hexane. This solution is then stirred for a period of 10 minutes at this temperature, after which time a solution of 2.0 g of ethyl 2-cyanoethyl(diethoxymethyl)phosphinate in 10 ml of tetrahydrofuran is added. This mixture is then stirred for a period of 1 hour at -78° C. after which time a solution of 1.4 g of benzyl bromide in 10 ml of tetrahydrofuran is introduced. This mixture is then allowed to warm to room temperature when 40 ml of a saturated ammonium chloride solution is added. The aqueous layer is then extracted with 2×25 ml of diethyl ether and the organic extracts are combined and dried over magnesium sulphate. The solvent is then evaporated under reduced pressure and the crude product chromatographed on silica gel using ethyl acetate as an eluent to give ethyl 2-benzyl-2-cyanoethyl(diethoxymethyl)phosphinate as a viscous oil, 31P=+40.7 and +40.5 ppm (CDCl3).

Quelle