Synthesis of 4′-Spironucleoside via Radical Translocation Cyclization Reaction

A novel synthetic strategy for the construction of 4′-spironucleosides via cascade radical translocation cyclization of N-allyl-N-(2′-bromophenyl) amide moiety of 5′-carboxylic nucleosides and the N-propynyl analogues is described. The conformationally restricted nucleosides herein synthesized are of potentially biological interests.