Phosphonium salts. III. The action of cyanide ion and other nucleophiles on some bis-phosphonium salts

Abstract

Cyclic and acyclic bis-phosphonium salts with a two-carbon bridge are smoothly cleaved to phosphines in high yield by potassium cyanide in dimethyl sulphoxide. Evidence is presented that the reaction proceeds by an elimination-addition sequence. An elimination reaction also occurs when sodium methoxide, sodium azide, sodium acetate, and triethylamine react with ethane-1,2-bis(tri-phenylphosphonium) dibromide.     In a novel reaction, triphenylphosphine is converted into its oxide by a mixture of sodium azide and dimethyl sulphoxide.