Abstract
Commercial phosphorus pentoxide reacts with some N-donor bases to give the adducts P(2)O(5)L(2) and P(4)O(10)L(3) (L = DABCO, pyridine, 4-tert-butylpyridine). The DABCO adducts were structurally characterized by single-crystal X-ray diffraction. It is proposed that P(2)O(5)L(2) and P(4)O(10)L(3) undergo interconversion through a "phosphate-walk" mechanism, which was evaluated using DFT calculations. P(2)O(5)(pyridine)(2) (1) efficiently transfers monomeric diphosphorus pentoxide to phosphorus oxyanion nucleophiles, yielding substituted trimetaphosphates and cyclo-phosphonate-diphosphates (P(3)O(8)R)(2-) (R(1) = nucleosidyl, phosphoryl, alkyl, aryl, vinyl, alkynyl, H, F). Hydrolytic ring-opening of these compounds forms linear derivatives [R(1)(PO(3))(2)PO(3)H](3-), and nucleophilic ring-opening gives linear disubstituted [R(1)(PO(3))(2)PO(2)R(2)](3-) compounds.