An efficient synthesis of highly optically active 4‐substituted‐2(5 H )‐furanones from chiral 3‐bromo‐2(5 H )‐furanone

Highly optically active 4‐substituted‐2(5 H )‐furanones 6a‐6j were obtained in good yields with de ⩾98% by the tandem Michael addition/elimination reaction of chiral 3‐bromo‐2(5 H )‐furanone (4a), which was conveniently prepared starting from 2‐furaldehyde under mild conditions. The products were identified on the basis of their satisfactory elemental analysis and spectroscopic data of IR, W, 1 H NMR, 13 C NMR and mass spectra. The stereochemistry and absolute configuration of this type of compounds were established by the X‐ray crystallographic study. The reaction provided a short and efficient synthesis of the interesting highly optically active 4‐substituted‐2(5 H )‐furanones containing an active pyrimidine and a purine base group.