Polymer-mediated cyclodehydration of alditols and ketohexoses

Abstract The polymer PEDOT + ( 1 or 2 ) mediates a cyclodehydration reaction with alditols 3 , 5 , 7 , 9 , in hydrocarbon solvents, to give cyclic ethers 4 , 6 , 8 , or 10 , respectively, in high yield with a trivial isolation protocol. Polymers 1 or 2 also mediate the cyclodehydration of ketohexoses such as d -fructose, but not aldohexoses, to the important industrial intermediate 5-hydroxymethylfurfural ( 17 ), under milder conditions when compared to reactions mediated by mineral acids. A cascade reaction with ketohexoses is observed in toluene via cyclodehydration followed by Friedel–Crafts alkylation of the initially formed benzylic alcohol to give 16 .