“…52 ± 54 Sulfurisation of macrocyclic tris(phosphoramidite) 49 results in a crystalline cis,cis,trans-product (one P atom is above and the other two P atoms are below the macrocycle plane); its structure was established by X-ray diffraction analysis. 53 Later on, dismutation of macrocyclic pentakis-(phosphoramidite) (see Section II.3) afforded the cis,cis,cisisomer of heterocycle 49 (all P atoms are on one side of the macrocycle), which significantly differs from the cis,cis,transisomer in properties. 54,55 Mention should be made of the possibility of bis(phosphoramidite) 4 formation in the first stage of this reaction.…”