Selective functionalization of imidazoles via an iodine-copper exchange reaction.

The reaction of protected 4,5-diiodoimidazoles with (PhMe2CCH2)2CuLi regioselectively provides 5-cuprated imidazoles, which readily react with various electrophiles furnishing functionalized imidazoles in good yields; remarkably, these resulting mono-iodoimidazoles undergo again an iodine-copper exchange reaction in the presence of sensitive functional groups, like an aldehyde or a ketone.