Saturated Rings with Phosphorus and Carbon

Phosphorus ring compounds have generally been less extensively studied than their nitrogen or purely carbocyclic analogues, and this limits the comparisons of physical and chemical properties which might otherwise be made. 

Although the first heterocycle containing both P and C atoms was reported by Gruttner and Wiernik as long ago as 1915 [23], it was not until the latter part of the century that significant numbers of these compounds began to be reported. 

The known saturated ring systems based on carbon and a single P atom are indicated in Table 6.19. Either trivalent Q ) or pentavalent (X. ) P may be involved. 

The phosphorus derivatives are considerably less basic than their nitrogen analogues, although in common with the latter, they form quaternary salts, the cations being 

Comparison of Saturated Ring Systems Based on One P Atom  

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