Compounds with P-C-Metal Linkages

Methylene trimethylphosphorane can be used to obtain a variety of ring compounds with P-C-M bonds. 

Mc3P AuMe + Mc3P=CH2 McjF-CHj-AuMe + MejP 

Some of the various phosphonium, ylidic and zwitterion types of compound are compared in Table 6.12. Those involving P-N linkages are discussed in Chapter 7. Most ylidic compounds can be regarded as stabilised by resonance with charged structures. In some ylids such as (g) (h) in Table 6.12, alternative double-bonded structures contribute as indicated in Equations (6.455, 6.444). Resonance of this kind is suggested by the experimental P-C distances, which lie between those of single and double bond values. 

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