Stabilized Molecular Diphosphorus Pentoxide, POL (L = -Donor Base), in the Synthesis of Condensed Phosphate-Organic Molecule Conjugates.

Commercial phosphorus pentoxide reacts with some -donor bases to give the adducts POL and POL (L = DABCO, pyridine, 4--butylpyridine). The DABCO adducts were structurally characterized by single-crystal X-ray diffraction. It is proposed that POL and POL undergo interconversion through a "phosphate-walk" mechanism, which was evaluated using DFT calculations. PO(pyridine) () efficiently transfers monomeric diphosphorus pentoxide to phosphorus oxyanion nucleophiles, yielding substituted trimetaphosphates and -phosphonate-diphosphates (POR) (R = nucleosidyl, phosphoryl, alkyl, aryl, vinyl, alkynyl, H, F). Hydrolytic ring-opening of these compounds forms linear derivatives [R(PO)POH], and nucleophilic ring-opening gives linear disubstituted [R(PO)POR] compounds.