Two-step cyanomethylation protocol: convenient access to functionalized aryl- and heteroarylacetonitriles

A two-step protocol has been developed for the introduction of cyanomethylene groups to metalated aromatics through the intermediacy of substituted isoxazoles. A palladium-mediated cross-coupling reaction was used to introduce the isoxazole unit, followed by release of the cyanomethylene function under thermal or microwave-assisted conditions. The intermediate isoxazoles were shown to be amenable to further functionalization prior to deprotection of the sensitive cyanomethylene motif, allowing access to a wide range of aryl- and heteroaryl-substituted acetonitrile building blocks.