Sulfur-Mediated ipso-Cyclization of 4-(p-Methoxyaryl)alk-1-ynes Leading to 3-Thiospiro[4.5]deca-1,6,9-trien-8-ones

Abstract

A new method for intramolecular electrophilic ipso-cyclization of alkynes with triflic anhydride activated sulfoxides followed by demethylation with triethylamine in one pot is described for the synthesis of 3-thiospiro[4.5]-decatrienones in moderate to good yields. This method provids a facile strategy to assemble the sulfur-substituted spirocyclic compounds.