Synthesis of 2′,3′-cyclohexen bicyclic uridine analogues using ring-closure metathesis

The synthesis of two new 2',3'-cyclohexen bicyclic uridine analogues is described. From 5'-protected uridine two successive tin radical-mediated allylations at 2'-C and 3'-C position followed by ring-closure olefin metathesis on the diene intermediate using Grubbs' catalyst led to the formation of the six-membered ring.