Trifluoromethylzinc compounds

Trifluoromethylzinc compounds can be prepared via the direct reaction of dihaloditluoromethane with zinc powder in DMF [J5] (equation 24) In this reaction, the DMF functions both as solvent and reactant Mechanistic experiments support a difluorocarbene reaction intermediate Indeed, a mixture of zinc and difluorodibromomethane in THF has been used for the synthesis of gewi-difluo-ro-cyclopropane derivatives [34 (equaUon 25)... 

Ligand exchange reactions can be used to prepare perfluoroalkylzinc compounds Solvated trifluoromethylzinc compounds can be synthesized via the reaction of dialkylzincs with bis(trifluoromethyl)mercury [36] (equation 27) A similar exchange process with bis(trif]uorometliyl)cadinium and diraethylzinc gives a mixture of tnfluoromethylcadmium and zinc compounds [77]... 

Trifluoromethylzinc compounds can be prepared by electrolysis of CF3Br in DMF between a zinc anode and a stainless steel cathode.7 Faradaic yields are higher than 100%, thus indicating the occurrence of a chemical route (Equation 8.10) at the surface of the anode along with the electrochemical process (Equation 8.9). 

It was found, in keeping with this, that the lower the current density, the greater the chemical attack at the anode. For example, at the low 5 mA cm"2 current density the faradaic yield of the formation of trifluoromethylzinc compounds is higher than 300%. This chemical process only takes place during electrolysis. 

Nucleophilic fluoroalkylation in the anomeric position has been performed with trifluorochloroethylene, or with perfluorovinyl ethers." The compound obtained with trifluorochloroethylene is an irreversible inhibitor of a-glycosidases (Figure 6.44). " Trifluoromethylzinc bromide can be used to perform the difluor-omethylation of hydroxyls in various positions, probably through a carbenic mechanism. 

Organofluorine Compounds and Fluorinating Agents. Part 18. Trifluoromethylzinc Bromide as a Reagent for the Preparation of Glycosyl Fluorides ... 

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