Fluorovinylzinc reagent

Typical examples of fluorovinylzinc reagents prepared by the direct insertion method are summarized in Table 1. 

In contrast to the extensive investigation of fluorovinylzinc reagents and their synthetic utility, only limited literature exists on fluorinated arylzinc reagents. Bis(pentafluorophenyl) zinc can be prepared by the reaction of zinc chloride with either pentafluorophenyllithium or pentafluorophenylmagnesium bromide (equation 70)64,65. An alternative route is via decarboxylation of zinc bis(pentafluorobenzoate) (equation 71)65. 

Preparation of a fluorovinylzinc reagent by direct metallation of a fluorovinyl halide preparation of 1,2,2-trifluoroethenylzinc bromide4,5... 

Pd(PPh3)4 catalysed coupling of a fluorovinylzinc reagent preparation of 1,2,3,3,3-pentafluoro-1-phenylprop-1-ene5... 

Generation and functionalization of a fluorovinylzinc reagent prepared by capture of a vinyllithium reagent preparation of 1,1-difluoro-2-trifluoromethylpenta-1,4-diene13... 

Copper halide transmetallation of a fluorovinylzinc reagent and refunctionalization of the copper reagent preparation of (Z)-1,1,2,5,5,5-hexafluoro-4-iodo-3-trifluoro methylpenta-1,3-diene15-16... 

A general discussion of the superior thermal stability characteristics of fluorovinylzinc reagents has been presented vide supra). Specifically, the fluorinated zinc reagents exhibit exceptional thermal stability. A sample of a [(Z)-pentafluoroprop-l-enyl]zinc halide in triglyme shows no loss of activity after three days at room temperature and only 10% of the zinc reagent decomposes after 36 days at room temperature. Upon heating at 65 C over three days, only 5 % of the zinc reagent decomposes, and a 25 % loss of activity is observed at the same tern-... 

It has been demonstrated that fluorovinylzinc reagents undergo stereoselective palladium-catalyzed coupling reactions with aryl (e.g., formation of 2 " ), vinyl (e.g., formation of heteroaryl, alkanoyl. and alkoxycarbonyl halides. Fluorovinylzinc reagents also undergo allyl-ation (e.g., formation of 4 ), halogenation, oxidative dimerization, and protonation reactions. ... 

Only a few reports of fluorovinylcadmium reagents exist. They are prepared in manners analogous to fluorovinylzinc reagents metathesis or cadmium insertion reactions. They undergo functionalization reactions similar to zinc reagents, although palladium-catalyzed coupling reactions have not yet been reported. 

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