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Potassium bromodifluoroacetate, which can be obtained from readily available ethyl ester, can be a practical alternative to Me3SiCF2Br in reaction with organozincs. Potassium bromodifluoroacetate could be used to synthesise gem-difluorinated compounds from organozinc reagents. Potassium bromodifluoroacetate serves as a source of CF2-fragment, which is inserted into the carbon single bondzinc bond of organozinc reagents. The intermediate difluorinated organozinc species can be protonated, brominated or coupled with allylic electrophiles[1].

The general procedure for the synthesis of potassium 2-bromo-2,2-difluoroacetate from ethyl difluorobromoacetate was as follows: to a methanol (500 mL) solution of potassium hydroxide (56 g, 1 mol) was slowly added ethyl difluorobromoacetate (203 g, 1 mol) at room temperature. The reaction mixture was stirred continuously at the same temperature until the ethyl bromodifluoroacetate was completely consumed. Upon completion of the reaction, the solvent was removed by concentration under reduced pressure to give potassium 2-bromo-2,2-difluoroacetate solid (202 g, 95% yield).

[1] Vitalij V. Levin. “Reactions of organozinc reagents with potassium bromodifluoroacetate.” Journal of Fluorine Chemistry 171 (2015): Pages 97-101.