Lewis acid-catalysed cyclization of pyridinium 1,4-zwitterionic thiolates with propargyl alcohols and fluorescence applications

Abstract

A new method for the efficient synthesis of thieno[3,4-c]furan-1-one derivatives through an intermolecular annulation strategy is reported. With an appropriate combination of Cu(OTf)₂ and 13X molecular sieves, a range of organosulfur compounds were obtained in good yields. Most of the obtained products exhibited good photophysical properties, and thieno[3,4-c]furan-4-carboxylate could be identified as a fluorescence sensor for Fe³⁺.