Aryl 2- pyridyl organometallic reagents

Tetrafluoropyridyl organometallic reagents can be prepared by reaction of 4-bromotetra-fluoro- or tctrafluoro-4-iodopyridine with zinc or cadmium in dimethylformamide at room temperature.83 Metathesis of these reagents with copper(l) bromide affords the (2.3,5,6-tetra-fluoro-4-pyridyl)copper reagent. The latter species undergoes high-yield substitution reactions with allyl halides, vinyl iodides, aryl iodides, and alkanoyl halides. 

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