The furan approach to thiacyclic compounds. Stereoselective synthesis of 2,3-disubstituted tetrahydrothiopyrans

We describe an efficient new approach to the synthesis of thiacyclic compounds that extends the methodology we previously developed for oxacycles: oxidation of a furan ring with singlet oxygen, followed by intramolecular hetero Michael addition. The new approach provides a new entry to nucleoside analogues and α-glucosidase inhibitors.