L-​nucleosides

This chapter provides an overview concerning the synthesis of L-nucleosides and their analogues. The first section deals with L-nucleosides, which maintain a close relationship with ribose and deoxyribose derivatives. The second section covers furanose nucleosides without the 2′ and 3′ hydroxyl groups. The third section talks about carbovir, which has been reported as the first carbocyclic nucleoside analogue, with potent anti-HIV activity in vitro; its discovery provided a base for the synthesis of other carbocyclic analogues. Among all types of aza-nucleosides, five-membered pyrrolidine-type nucleosides have been investigated particularly because of their high similarity with naturally occurring nucleosides. Next, the chapter talks about the thionucleosides. Several purine and pyrimidine-L-dioxolane nucleosides have been reported using the acetoxy dioxolane 370 as a glycosyl donor for condensation under classical Vorbrüggen conditions. The final section talks about the oxathiolanyl nucleosides.