ChemInform Abstract: The Generation of Metaphosphoramidates by Fragmentation of 2,3- Oxaphosphabicyclo(2.2.2)octene Derivatives.

Abstract

Abstract Phosphole oxides with N,N-diethylamino, N-mesitylamino and N-tert-butylamino substituents on phosphorus were generated in the presence of N-phenylmaleimide to give Diels-Alder adducts with the 7-phosphanorbornene framework. Products were characterized by 31P and 13C NMR spectroscopy, and in one case by 17O NMR spectroscopy. Insertion of oxygen into a P[sbnd]C bond of this strained cyclic system occurred smoothly on treatment with m-chloroperbenzoic acid. The resulting derivatives with the 2,3-oxaphosphabicyclo[2.2.2]octene ring system were characterized by 1H, 31P, and 13C NMR spectroscopy. In the case of the N-mesityl derivative, two stable isomers were formed and separated by chromatography. The full structure of one isomer was established by X-ray diffraction analysis. The ring system was fragmented on heating in toluene (110°C, 22–48 hrs) or on irradiation (30–35°C, 254 nm, 24 hrs) with the release of the P[sbnd]O bridging unit as a metaphosphoramidate (RR′N[sbnd]PO.). In the photolytic metho...