(2,6)3P=S] reacted with acids to form a novel mercaptophosphonium salt [(2,6)3P–SH]X, solution thermolysis of which in the absence or presence of triphenylphosphine resulted in the unusual desulfurization to give the tertiary phosphonium salts [(2,6)3P–OH]X. (2,6)3P=S also reacted with alkyl iodides or bromides under mild conditions to give stable (alkylthio)phosphonium salts [(2,6)3P–SR]X (R=Me, Et
Tris(2,6-dimethoxyphenyl)phosphine sulfide reacted with alkyl iodides or bromides under mild conditions to give stable alkylthiophosphonium salts, which reacted with thiols at room temperature in the presence of a catalytic amount of tris(2,6-dimethoxyphenyl)phosphine to give the tertiary phosphonium salt and unsymmetrical disulfides.