O-ALKYLATION D'AMIDES A L'AIDE DE SELS D'ALKYLDIPHENYLSULFONIUM

Article abstract of DOI:10.1016/S0040-4020(01)88543-4

O-Alkylation of amides and ureas was easily accomplished with alkyldiphenylsulphonium salts.These alkylating agents are readily available, often crystalline, and non-hygroscopic.They are somewhat less powerful than oxonium salts but are not limited to methyl and ethyl groups.The following order of reactivities was observed: PhCH2S(+)Ph2<*>EtS(+)Ph2<*>Et2SO4<*>MeS(+)Ph2.Benzylation proceeded under very mild conditions (room temperature).The counterion and solvent have no significant influence on the reaction rate.Sulphonium salts where the leaving group is a dialkyl sulphide are much less active as alkylating agents.New alkoxymethyleneiminium salts have been prepared in this way in yields above 70 percent.