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

摘要

Tributyltin radical mediated cyclization of the glucose derived exo-methylene furanose derivatives 5a-c led to the highly functionalized cis-fused bicyclic ethers 6a-c. The product could subsequently be transformed to the optically active tricyclic nucleoside analogue 8 or oxepine derivative 9. (c) 2005 Elsevier Ltd. All rights reserved.