Geminal Silicon/Zinc Reagent as an Equivalent of Difluoromethylene Bis-carbanion

A new
difluorinated reagent, [difluoro­(trimethylsilyl)­methyl]­zinc
bromide, bearing C–Zn and C–Si bonds is described. The
reagent is conveniently prepared by cobalt-catalyzed halogen/zinc
exchange. It can be coupled with two different C-electrophiles in
a stepwise manner (with allylic halides for C–Zn bond and aldehydes
for C–Si bond) affording products containing a difluoromethylene
fragment.