The alkaline hydrolysis of sterically crowded phosphonium salts

Abstract

Di-t-butylphosphonium salts are extremely resistant to alkaline hydrolysis. Benzyl(phenyl)di-t-butylphosphonium bromide with aqueous alkali slowly gives isobutene and benzyl(phenyl)-t-butylphosphine. With sterically crowded phosphonium salts, e.g. benzyl-α-naphthylphenyl-t-butylphosphonium bromide, the normal rule, that hydrocarbon will be formed from that group most stable as the anion, does not apply. Factors which may be responsible for this are discussed.