In contrast to aliphatic thiocyanates, which react with trialkyl phosphites exclusively by an Arbuzov mechanism to form phosphorothioates, aromatic thiocyanates, ArSCN, react with trialkyl phosphites,(RO) 3P, to give a mixture of phosphorothioate and sulfide, RSAr. The formation of sulfide is favored by substituents (NO?, etc.) on the aryl ring that can stabilize an anionic species, an observation that suggests a mechanism involving attack of phosphite ...
