Synthesis and Molecular Structure of Heterocycles Containing two Phosphorus(V) Centers Bridged by Two-Coordinate Phosphorus and Arsenic

✍ Scribed by Gamper, Siegfried F. ;Schmidbaur, Hubert

• Publisher: Wiley (John Wiley & Sons)
• Year: 1993
• Tongue: English
• Weight: 389 KB
• Volume: 126
• Category: Article
• ISSN: 0009-2940
• DOI: 10.1002/cber.19931260309

✦ Synopsis

Arsadiphosphabenzenes 1,l-Bis[(diphenylphosphanyl)methyl]ethene (3) reacts with PC13 or AsCl, in the presence of SnC12 as a reducing agent to form cationic heterocycles in which the two newly generated phosphonium centers are bridged by two-coordinate, negatively charged phosphorus (4a) or arsenic (4b) centers. Hexachlorostannate(1V) dianions function as counterions to these heterocycles, in which the exocyclic methylene group is retained. By treatment of 4a with a base a rearrangement is induced which includes a proton migration from an endoto the exocyclic CH2 group to give 5-methyl-l,1,3,3-tetra-phenyl-lh5,2h3,3h5-triphosphinine (5), a novel 1,2,3-triphosphabenzene species. The reaction of the arsenic compound 4b with base did not yield the corresponding arsa-diphosphabenzene, but gave only decomposition products. Compound 4 b . 0.5 CH3CN has been studied by X-ray crystallography.