Stabilized Molecular Diphosphorus Pentoxide, P 2 O 5 L 2 (L = N -Donor Base), in the Synthesis of Condensed Phosphate-Organic Molecule Conjugates.

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.