[CH3:1][O:2][C:3](=[O:19])[CH2:4]P(OCC(F)(F)F)(OCC(F)(F)F)=O.[Br:20][C:21]1[CH:28]=[CH:27][C:24]([CH:25]=O)=[CH:23][CH:22]=1>C1COCC1.[NH4+].[Cl-].C(Cl)Cl>[CH3:1][O:2][C:3](=[O:19])/[CH:4]=[CH:25]\[C:24]1[CH:27]=[CH:28][C:21]([Br:20])=[CH:22][CH:23]=1To a solution of [Bis-(2,2,2-trifluoro-ethoxy)-phosphoryl]-acetic acid methyl ester (1.0 eq.) and 18—C-6 (5.0 eq.) in THF (0.05M) at −78° C. was added dropwise KN(TMS)2 (1.0 eq.). The mixture was stirred at −78° C. for 15 min then 4-bromobenzaldehyde (1.0 eq.) was added. The final mixture stirred for 1 h at −78° C., poured in saturated aqueous NH4Cl and extracted with Et2O (3×). The combined organic extracts were washed with, brine, dried over Na2SO4, filtered and concentrated. Flash chromatography (Hex:EtOAc 10 to 25%) afforded a mixture of desired material and the starting aldehyde. Upon treatment in CH2Cl2 of the mixture with Amino-Merrifield resin for 10 min, the aldehyde was removed. Filtration and concentration afforded the title compound as an oil.
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