Efficient Synthesis of 4′-Cyclopropylated Carbovir Analogues with Use of Ring-Closing Metathesis from Glycolate

The first synthetic route of novel 4′-cyclopropylated carbovir analgues is described. The construction of cyclopropylated quaternary carbon at 4′-position of carbocyclic nucleosides was successfully made via sequential Johnson's orthoester rearrangement and ring-closing metathesis (RCM) starting from ethyl glycolate. Synthesized compounds 15 and 16 showed moderate antiviral activity without any cytotoxicity up to 100 μmol.