Trapping and Competition Experiments

Pentacoordinate species (phosphoranes) are proposed intermediates in the hydrolysis of RN A and DNA. Before such species were well accepted, chemists examined the chemistry of phosphoesters such as i as model systems. Compound i can cyclize to give phosphorane ii, although a was never. seen at room temperature. However, upon adding acetyl chloride to a solution of /, both Hi and iv are isolated. Trapping experiments such as this one give good 

E Crystal and MolecularStructureof Phosphate Esters. 9. Crystal and Molecular Structure of oHydroxyphenyl-ophenylenc I hosphale, (( -HOChH4)(Q,H4)P04. Equilibrium Between Pentavalent and Telravalent Phosphorus in Solutions. /. Aw. Chew. Sac., 100,5391 (1978). 

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