Polycyclic derivatives of hexacoordinated phosphorus atom with transannular N→P bond

Abstract

Reaction of diimine I containing phenol groups with ethylenechlorophosphite II was established to undergo a stereoselective cascade cyclization giving rise to tetracyclic derivative III of the hexacoordinated phosphorus atom with intramolecular transannular N→P bond. The structure of compound III was proved by the IR, Н and Р NMR spectroscopy, mass spectrometry, X-ray diffraction method, and the composition was established by the elemental analysis data. The IR spectrum of the product III contains absorption bands at 1629 (С=N) and 2500–2680 cm (broadened complex band, NH2). The chemical shift of the phosphorus atom δP –115.84 ppm is characteristic of the phosphorus hexacoordinated derivatives. Due to salt structure, the Н NMR spectrum of compound III contains poorly resolved signals permitting only group analysis of the protons on the basis of chemical shifts without considering its fine structure. By the elemental analysis data compound III has the overrated percentage of chlorine. This suggests that the compound contains a solvent, methylene chloride. This conclusion was confirmed by the X-ray diffraction data. The product III actually crystallized as a complex with methylene chloride molecule as one diastereoisomer. Configurations of asymmetrical centers on the carbon and phosphorus atoms are opposite. The transannular N→P bond length is 2.006(6) A. The intermolecular bonding of similar type was earlier observed in the series of hexacoordinated phosphorus derivatives [1–5]. DOI: 10.1134/S1070363210020325