[CH3:1][O:2][C:3]([CH2:5]P(OC)(OC)=O)=[O:4].[Li+].CC([N-]C(C)C)C.[F:20][C:21]1[C:26]([O:27][CH3:28])=[CH:25][CH:24]=[CH:23][C:22]=1[C:29]([CH3:33])([CH3:32])[CH:30]=O.O>C1COCC1.CCCCCCC.C(C1C=CC=CC=1)C.O1CCCC1>[CH3:1][O:2][C:3](=[O:4])/[CH:5]=[CH:33]\[C:29]([C:22]1[CH:23]=[CH:24][CH:25]=[C:26]([O:27][CH3:28])[C:21]=1[F:20])([CH3:30])[CH3:32]
20.26 g (111.26 mmol) of phosphonoacetic acid trimethyl ester is introduced into 68 ml of tetrahydrofuran. At 0° C., 61 ml of a 2 M solution of LDA in THF/heptane/ethylbenzene is added in drops. After 45 minutes of stirring, 21.83 g (111.26 mmol) of 2-(2-fluoro-3-methoxyphenyl)-2-methylpropanal, dissolved in 68 ml of tetrahydrofuran, is added in drops at 0° C. After stirring overnight, the reaction mixture is mixed with water while being cooled in an ice bath, and it is extracted three times with methyl tert-butyl ether. The combined organic extracts are treated as usual, and the residue that is obtained is chromatographed on silica gel (mobile solvent ethyl acetate/hexane). 23.30 g (75.8%) of the desired compound is isolated.
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