Ansa versus spiro selectivity in substitution reactions of a mono ansa fluorodioxycyclotriphosphazene derivative with diols

In this study, regio-selectivity in the nucleophilic substitution reactions of a mono ansa fluorodioxycyclotriphosphazene derivative with diols has been investigated. The cyclotriphosphazene derivative, N3P3Cl4[OCH2(CF2)3CH2O] (1), was reacted with the disodium salts of 1,3-propanediol and tetraethyleneglycol in THF solution at a 1:1 M ratio and eight new products (2–6, 7a, 7b and 8) were formed. These products were separated and characterized by elemental analysis, mass spectrometry, 1H and 31P NMR spectroscopy. The crystal structures of 2, 3, 5, 6 and 7a have been characterized by X-ray crystallography. The spiro derivatives (3, 6) were formed as the major product in the reactions of compound 1 with both diols.

Graphical abstractThe nucleophilic substitution reactions of cis-ansa fluorodialkoxycyclotriphosphazene with disodium salts of diols occur preferentially at the PCl2 groups rather than at the P(OR)Cl moieties and so spiro derivatives are the major product in the reactions.Figure optionsDownload full-size imageDownload as PowerPoint slide