Toluene → (E)-2-cyano-3-(2,2-difluoro-1,3-benzodioxol-4-yl)-2-propenoic acid ethyl ester

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Reaction Steps

53.3 g (337 mmol) of 2,2-difluoro-1,3-benzodioxole in 46 ml of toluene are metallated according to Example 2d), at from -15° to -10° C., with 137.8 g (409 mmol) of n-butyllithium solution (19.0% in toluene) in the presence of 39.3 g (339 mmol) of TMEDA. 69.1 g (409 mmol) of ethoxymethylenecyanoacetic acid methyl ester in 150 ml of toluene are metered in at from -15° to -10° C. over a period of 21/2 hours. The reaction mixture is added at +10° C. to 450 ml of water, the phases are separated and the organic phase is concentrated by evaporation in a vacuum rotary evaporator to yield the title compound.

Provenance & Evidence