Some substitution reactions at the phosphorus of 2,2,3,4,4-pentamethyl-phosphetans

Abstract

Nucleophilic substitutions at the phosphonium or phosphoryl centres of 2,2,3,4,4-pentamethylphosphetans proceed with retention of configuration at the phosphorus. 1-Aryl-2,2,3,4,4-pentamethylphosphetan oxides when treated with aryl-lithiums give aryl-(3-aryl-1,1,2,3,3-pentamethylpropyl)phosphine oxides. Additional evidence, involving deuterium labelling, is presented for the spirocyclohexa-1,4-diene structure (III) for the oxide from the alkaline hydrolysis of 1,2,2,3,4,4-hexamethylphenylphosphetanium iodide.