Mimics of l -rhamnose: Synthesis of C-glycosides of L-rhamnofuranose and an α-azidoester as divergent intermediates for combinatorial generation of rhamnofuranose libraries

The ring contraction of readily available δ-lactones provides a short route to the synthesis of both epimers of C-L-rhamnofuranosides, radical bromination of which give access to an α-azidocarboxylate as a divergent intermediate for applying combinatorial methodology for the preparation of a wide range of mimics of L-rhamnofuranose; such materials may provide an approach to the study of the biosynthesis of the cells walls of mycobacteria such as Mycobacterium tuberculosis and M. leprae.