SOLVATION AND METAL-ION EFFECTS ON STRUCTURE AND REACTIVITY OF PHOSPHORYL COMPOUNDS .2. BETA,GAMMA-SUBSTITUTED ALKYLPHOSPHONIC ESTERS

NMR spectroscopic and conformation analyses ware carried out for five dimethyl beta,gamma-disubstituted propylphosphonates, YCH2CHXCH2PO3Me2 , in five solvents and in acetone containing sodium and magnesium ions . Conformational preferences observed for the rotation about the C1-C2 bond are determined by the attractive interactions between the oxygen containing substituents X (X=OH, OMe) and the phosphoryl group, and a re enhanced by the metal ions, presumably via chelation effects. The r otation about the C2-C3 bond yields statistical distribution of the ro tamers. For Y = benzoyl, there was no evidence for a competition of th e carbonyl group for the intramolecular interactions with X or with a metal ion.