Functionalized magnesium organometallics as versatile intermediates for the synthesis of polyfunctional heterocycles.

In the last few years, we have demonstrated that the halogen/magnesium-exchange reaction is a unique method for preparing a variety of new functionalized aryl, alkenyl, heteroaryl magnesium compounds which has considerably extended the range of functionalized Grignard reagents available for synthetic purposes. A variety of functional groups such as an ester, nitrile, iodide, imine and even sensitive groups like nitro, hydroxyl and boronic ester can be tolerated in these organomagnesium compounds. We wish to describe the application of this halogen/magnesium-exchange reaction for the preparation of a broad range of five- and six-membered functionalized heteroaryl magnesium compounds and their reactions with various electrophiles providing a new entry to a range of polyfunctional heterocycles such as thiophene, furan, pyrrole, imidazole, thiazole, antipyrine, pyridine, quinoline and uracil derivatives.