Apicophilicity of the benzoyl group in five-co-ordinate phosphoranes

Abstract

Evidence is presented from the variable-temperature ¹H n.m.r. spectrum of 5-benzoyl-2,2,3,3,7,7,8,8-octamethyl-1,4,6,9-tetraoxa-5-phosphaspiro[4.4]nonane (9) that the apicophilicity of the benzoyl group is comparable to those of the phenoxy- and phenylthio-groups. Benzoyldifluorodimethylphosphorane is prepared from benzoyl-dimethylphosphine and xenon difluoride. Its low temperature ¹⁹F and ¹H n.m.r. spectra give some evidence for restricted rotation round the equatorial P-benzoyl bond.