Synthesis of N-glycosides. An alternative approach based on diastereoselective base coupling and S(N)2 cyclization.

[reaction: see text] Acyclic diastereoselection is achieved for the formation of thioaminyl acetals. The highly intramolecular stereocontrolled S(N)2 displacement of the thioaminyls allows for the formation of cyclic nucleoside derivatives. This versatile approach may provide easy access to a large variety of N-glycosides.