Electrophiles diorganozinc reactivity

Since the early disclosure by Negishi that zinc halide salts accelerate Pd(0) -catalyzed crosscouplings between vinyl zirconocenes and various halides [78], several methods have been developed that extend the utility of this metathesis process from a zirconium chloride to a zinc chloride (79 Scheme 4.47). Alternatively, routes to more reactive diorganozinc intermediates, e. g., using Me2Zn, convert readily available zinc derivatives to mixed species 80, which selectively couple with various electrophiles [14]. 

Diorganozincs are usually more reactive totvard electrophiles than organozinc halides. A tvide range of methods is available for their preparation. The oldest being the direct insertion of zinc to an alkyl halide (usually an alkyl iodide) lead-... 

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