Synthesis of conformationally restricted 2',3'-exo-methylene carbocyclic nucleosides built on a bicyclo[3.1.0]hexane template.

A series of 2',3'-exo-methylene carbocyclic nucleosides was synthesized as potential antiviral agents. These compounds were built on a bicyclo[3.1.0]hexane template that exhibits a rigid pseudoboat conformation and is capable of maintaining an identical conformation in solid state and in solution. The structures of the synthesized compounds were elucidated by NMR and X-ray crystallography. All the compounds were tested as anti-HIV and anti-HSV agents. The chemically synthesized 5'-triphosphate analogue of 7 was evaluated directly as a reverse transcriptase inhibitor.