The ring contraction of δ-lactones with leaving group α-substituents: a strategy for the synthesis of 2,5-disubstituted highly functionalised homochiral tetrahydrofurans

Abstract
Treatment of derivatives of δ-lactones having a leaving group at C-2 with methanol in the presence of base gives methyl tetrahydrofuran-α-carboxylates in good to excellent yield with a high degree of stereocontrol of the carbon substituents at C-2 and C-5.