Acid-catalysed transformation of α-trifluoromethanesulfonates of γ- and δ-lactones into 2,5-disubstituted homochiral tetrahydrofurans

Abstract

Excellent yields of methyl tetrahydrofuran-α-carboxylates are obtained by treatment of 2-O-trifluoromethanesulfonates (triflates) of either 1,4-or 1,5-lactones with acid in methanol; in some cases, very different tetrahydrofurans may result from acid or base treatment of a methanolic solution of the same starting material.