5-(2-Fluoro-3-methoxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione → HCID 57705536, Verbindung

A 500 mL round bottom flask was charged with 5-(2-fluoro-3-methoxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione 77.B (5.00 g, 17.8 mmol) and THF (100 mL). The resulting slurry was cooled to 0° C., and to it was added ethylmagnesium bromide (available from Aldrich) (3.0 M/ether) (11.9 mL, 35.7 mmol) dropwise over 15 minutes. The cooling bath was removed, and the mixture was stirred for 1 hour at ambient temperature. The reaction was quenched with 1 N HCl and extracted with EtOAc. The combined organic layers were washed with brine, dried (MgSO4), and concentrated to afford 5-(1-(2-fluoro-3-methoxyphenyl)propyl)-2,2-dimethyl-1,3-dioxane-4,6-dione 77.C (5.17 g, 93.4% yield) as a yellow oil (5.2 g, 93%). The product thus obtained was used without further purification.