Conversion of Carbonyl into gem-Difluoromethylene

The formation of typical by-products, mostly rearrangement products, can be explained on the basis of this mechanism. 

As in the fluorination of alcohols, here also the most important side-reactions are elimination and rearrangements. As demonstrated for pivaldehyde as example (Table 2.1), the product distribution depends critically on the choice of a suitable reaction solvent. Non-polar solvents (CFCl, pentane, or CHjCIj) favor the 

---