Polycyclic phosphanes

Baudler M, Glinka K (1993) Monocyclic and polycyclic phosphanes. Chem Rev 93 1623-1667... 

Goh LY, Wong RCS, Sinn E. 1993. Novel polycyclic phosphane-to-metal coordination. Reaction of (CpCr(CO)3)2 with elemental phosphorus and structure and paramagnetism of the odd-electron complex (CpCr(CO)2)5P 10. Organometallics 12(3) 888-894. 

As obviously small substituents do not influence the structures of the polycyclic phosphane skeletons, the substitution of methyl groups by hydrogen atoms should not cause any change. 

If the CH or CR increments in the carbon cages are substituted by valency isoelectronic phosphorus(III) moieties, we enter the field of polycyclic phosphanes — an area that has experienced a tremendous development in the past few years. It may now be safely assumed that, second to carbon, phosphorus is the element with the most pronounced ability to form element-element bonds [7]. From the enormous range of fascinating phosphorus cage structures, we need only mention the polycyclic systems 4 [8] and 5 [9] as typical examples. 

The common link between the two areas of research mentioned above (carbon cages and polycyclic phosphanes) is provided by the phosphorus-carbon cage compounds — the topic of the present chapter. In accord with the philosophy of this book, we will concentrate mainly on the results from our own laboratories and outline their position in the wider perspectives... 

When phosphaalkynes are exposed to bis- and tris(diazo) compounds, bis- or tris(l,2,4-diazaphosphol-5-yl) compounds are formed that may be further converted into a variety of novel heterocyclic systems. For example, bis- and tris[diazo(tri-methylsilyl)methyl]phosphanes 237 and 240 afforded bis- and tris(diazaphospho-lyl)phosphanes 238 and 241 after cycloaddition with terf-butylphosphaacetylene followed by a subsequent 1,5-silyl shift (Scheme 8.56) (300). Reaction with electrophilic halides at the Wsilyl functions allows the introduction of a heteroatom bridge between the diazaphosphole ring leading to polycyclic ring systems such as 239 and 242. 

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