Radical cyclization of exo-methylene furanose derivatives: an expedient approach to the synthesis of chiral tricyclic nucleosides and benzannulated oxepine derivatives

Tributyltin radical mediated cyclization of the glucose derived exo-methylene furanose derivatives led to the highly functionalized cis-fused bicyclic ethers . The product could subsequently be transformed to the optically active tricyclic nucleoside analogue or oxepine derivative .