Pentacoordinated and Hexacoordinated Compounds

The year has seen a considerable extension of the principles of hypervalent phosphorus chemistry into the fields of other elements notably Si, Sn, Ge and Sb and in this context the well-known Martin ligand has proved to be especially valuable. Particularly interesting contributions have been provided by Ju et al on the relative rates of reaction of pentoses and hexoses with pentacoordinate phosphorus, by Bentrude et on the mechanism of the reaction of hy-dridophosphoranes with dimethyl disulfide and by Kawashima et alP on the isolation of two carbaphosphatranes containing covalent P-C bonds. Holmes et al report on the fluxional properties of propeller shaped phosphoranes and Buono et have also demonstrated the utility of hydridophosphoranes in some highly diastereoselective reactions with isocyanates. In summary, although the number of reports was small, the year was noteworthy for some very sophisticated contributions to the field. 

Trichloro-(o-phenylenedioxy)phosphorane(l) reacts with (2a-e) to give chloro- 

Organophosphorus Chemistry, Volume 33 The Royal Society of Chemistry, 2003 

High resolution mass spectrometry and multinuclear NMR/IR spectroscopy have been used to show that the products of the reaction of 2,2,2-trichloro-5-halobenzo[d]-l,3,2 X, -dioxaphospholes with phenyl- and p-bromophenylacety-lenes are trihalogenated six-membered heterocycles. For example the 5-chloro analogue (5) reacts with phenylacetylene (6) to give (7) and the incorporation of two chlorine atoms in positions 6 and 7 of the product was proved by X-ray crystallography of the hydrolysis product (8).  

In a paper dealing with the reactions of methylenediphosphines with hexa-fluoroacetone (HFA) and hexafluorothioacetone (HFTA) dimer, Roschenthaler 

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Pentacoordinated and Hexacoordinated Compounds 4 Bicyclic and Tricyclic Phosphoranes... 

Pentacoordinated and Hexacoordinated Compounds G.-V. Rdschenthaler and Romana Pajkert 290... 

Pentacoordinated and hexacoordinated compounds Romana Pajkert and Gerd-Volker Rdschenthaler 1 Introduction 2 Pentacoordinated phosphorus compounds 3 Hexacoordinated compounds References 354 354 354 366 374... 

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