<p>The trivalent phosphorous atom of a compound is reacted with a reagent in such a manner that a stable phosphate mimetic is formed. Phosphoramidites with a phosphorous atom containing at least one hydroxyl residue which is provided with a protective group are reacted for this purpose with a free hydroxyl group: In the first synthesis cycle the hydroxyl group is linked to a solid support via a cleavable or non-cleavable linker. In further synthesis cycles the hydroxyl group is created by cleavage of the protective group from the growing oligomer. This results in formation of a phosphorous acid triester which is reacted with azides. Compounds of Formula (I) are produced.</p>
