Trifluorovinylzinc reagent

Heinze and Burton reported the first practical synthesis of a,/S,/S-trifluorostyrenes via the palladium-catalyzed coupling of the trifluorovinylzinc reagent with aryl iodides29 (equation 48). This methodology avoided the low temperatures in the earlier tetrafluo-roethylene route47, avoided side products (stilbenes) and/or multi-step procedures that plagued earlier reports of this important olefin29. 

Spawn and Burton investigated the reactions of the trifluorovinylzinc reagent with acyl halides. The reactions were sluggish and gave low yields of the trifluorovinyl ketones. Flowever, with Cu(I)Br catalysis, the acylation occurred rapidly and gave excellent yields of the trifluorovinyl ketones (equation 65)58. 

Yamamoto and coworkers utilized the resultant product from the palladium catalyzed reaction of l-fluoro-2-iodobenzene with the trifluorovinylzinc reagent to prepare a tri-fluorovinylimide, which on thermal dimerization at 140-160 °C gave predominantly the -cyclobutane, whose structure was established by X-ray crystallography (Scheme 4)60. 

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