Triethyl 2-phosphonopropionate → Diethyl 1-ethoxycarbonyl-4-methyl-pent-3-ene-1-phosphonate

Reaction equation

[Na].[CH2:2]([O:4][C:5]([CH:7]([P:9](=[O:16])([O:13][CH2:14][CH3:15])[O:10][CH2:11][CH3:12])[CH3:8])=[O:6])[CH3:3].Br[C:18]([CH3:22])([CH:20]=C)[CH3:19]>C(O)C>[CH2:2]([O:4][C:5]([CH:7]([P:9]([O:10][CH2:11][CH3:12])(=[O:16])[O:13][CH2:14][CH3:15])[CH2:8][CH:19]=[C:18]([CH3:22])[CH3:20])=[O:6])[CH3:3]

Participants

Procedure

The diethyl 2-ethoxycarbonly-5-methyl-hex-4-ene-2-phosphonate used in this reaction was prepared by the following procedure. 4.8 Parts of sodium metal were dissolved in 200 parts of absolute ethanol and to this solution was added 50 parts of diethyl 1-ethoxycarbonyl-ethylphosphonate. To this stirred reaction mixture at room temperature was added 31.3 parts of 2-bromo-2-methyl-but-3-ene dropwise over 1 hour. On completion of the addition stirring was continued for 1 hour at room temperature and then for 2 hours at 60° C. After cooling, the reaction mixture was filtered free of sodium bromide and the filtrate concentrated under reduced pressure to remove ethanol. The residual oil was taken up in ether, and the ether solution washed with water and evaporated. Fractional distillation of the residue gave diethyl 1-ethoxycarbonyl-4-methyl-pent-3-ene-1-phosphonate b0.3 126°-34° C. with the following percentage composition by weight.