Compounds with Three-Connected P Atoms

Some compounds of the types indicated in Table 6.14 are believed to have been synthesised. Most of these compounds contain some trimethylsilyl, ter-2,4,6 butylphenyl or other bulky stabilising groups. Some typical syntheses are (6.620-6.623) [7,8]. Bis methylene phosphoranes were discovered by Appel and co-workers in 1982 [9]. 

Dioxophosphoranes (metaphosphonates) (Table 6.14) are also somewhat unstable and are liable to polymerise (6.626). The monomer has been observed as a mass spectral fragment from the decomposition of certain oxyphosphetanes. Monometaphosphates (R = OH in (6.626), are not isol-able [10,11] (Chapter 5.3). 

The polymerised metaphosphonates (RP02) (R = Me, Et, Bu, Ph) form not-too-well defined solids whose mass spectra indicate the predominant species are trimer rings as in (6.626) [12], 

A planar 3-coordinated compound of type (d) in Table 6.14 is in reaction [8], 

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