Synthesis of conformationally locked carbocyclic nucleosides built on an oxabicyclo[3.1.0]hexane system

The rigid 6-oxobicyclo[3.1.0]hexane scaffold, characteristic of the natural antibiotic neplanocin C (), was used to build prototypes of conformationally locked deoxynucleosides in the North hemisphere of the pseudorotational cycle. The purine analogues and are conformationally equivalent to carbocyclic nucleosides built with the bicyclo[3.1.0]hexane template. The pyrimidine nucleosides were unstable and underwent a facile intramolecular epoxide ring-opening reaction leading to heterocycle . Only the deoxyguanosine analogue showed antiviral activity against EBV.