Polycyclic Oxyphosphoranes

Survey of Experimental Data A. Caged Polycyclic Oxyphosphoranes 

The caged pentaoxyphosphorane (33)55-60 is obtained from the adamantenoid phosphite104-108 (32), and hexafluoroacetone (3). 

In the static TBP shown in Fig. 13 there are two types of methine protons, two types of cyclohexane-equatorial and two types of cyclohexane-axial methylene protons, and two types of fluorines. Yet, the n.m.r. spectra of this compound in solution at + 30°, which is summarized in Table 13, exhibits only one signal (tCh) for the methine protons, one signal for the equatorial and one signal for the axial methylene protons of the cyclohexane (rCHl), and one signal for the fluorines. These spectra 

Compound No. S 31P 8 F tch /hcop tch Jhcop Relatively sharp signal above Coalescence Relatively sharp signal below  

The positional exchange of ligands in phosphorane (33) occurs by a regular, and not by an irregular, permutational isomerization process. This conclusion is supported by the data given in Table 14, and by the following arguments  

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