Synthesis and Characterization of 2-Arylseleno-2-chloro-1,2,3-triorgano-1,3,2λ5-diazaphosphetidin-4-ones

The reactions of N,N′-dimethyl-N,N′-bis(trimethylsilyl)urea 8 and N-methyl-N′-phenyl-N,N′-bis(trimethylsilyl)urea 9 with phenylselenenyl chloride 6 and p-chlorophenylselenenyl chloride 7 furnished the N-arylseleno-N,N′-diorgano-N′-(trimethylsilyl)ureas 10–13 . The reactions of 10–13 with MePCl₂ and PhPCl₂ resulted in the formation of a new class of compounds, the 2-arylseleno-2-chloro-1,2,3-triorgano-1,3,2λ⁵-diazaphosphetidin-4-ones 14–19 . The new selenophosphoranes 20 and 21 were obtained in the reaction of 15 and 17 with p-nitrophenol in the presence of triethylamine. The identity and structure of the new compounds were established by ¹H- and ¹³C-NMR spectroscopy, elemental analysis, ³¹P- and ⁷⁷Se-NMR spectroscopy in the case of the selenophosphoranes 14–21 , and mass spectrometry in the case of 11 and 13 . A possible mechanism of the reaction leading to the selenophosphoranes is discussed. Single-crystal X-ray structure analyses of the selenophosphoranes 19 and 20 were conducted. Both display distorted trigonal bipyramidal geometry at phosphorus, the major distortions being imposed by the four-membered rings.