18-Crown-6 → Methyl 4-[1-{4-[2-(tert-butoxy)-1,1-difluoro-2-oxoethoxy]benzyl}-1-{4-[[di(tert-butoxy)phosphoryl](difluoro)methyl]benzyl}-2-(4-fluorophenyl)-2-oxoethyl]benzoate

Participants

Reaction Steps

To a solution of methyl 4-[1-{4-[2-(tert-butoxy)-1,1-difluoro-2-oxoethoxy]benzyl}-2-(4-fluorophenyl)-2-oxoethyl]benzoate (0.176 g, 0.333 mmol)) in degassed THF (1.7 ml), were added at −20° C. 18-crown-6 (0.15 g) and potassium tert-butoxide 1 M in THE (0.379 ml ). Di(tert-butyl) [4-(bromomethyl)phenyl](difluoro)methylphosphonate (0.156 g, 0.378 mmol) was then added and the reaction mixture was allowed to warm to room temperature. The reaction was quenched with saturated ammonium acetate solution and extracted with ethyl acetate. The organic phase was dried over sodium sulfate, filtered and evaporated to dryness. The residue was purified by flash chromatography using hexane/ethyl acetate 20% giving 0.140 g of the title compound.

Provenance & Evidence