Detailed syntheses of carbovir-related cis-[2-(9H-Purin-9-yl)-3-cyclopentene]-1-methanols and phosphonates of selected analogues are presented. Our interest in this chemistry stems from antiviral activity shown by closely related compounds. Access to the key β-lactam was achieved by the reaction of monocyclopentadiene with chlorosulfonyl isocyanate at− 78° C rather than at the reported 1 ambient temperature, where only the less ring-strained and ...
![2-Azabicyclo[2.2.1]hept-5-en-3-one Structure](https://image.chemsrc.com/caspic/088/49805-30-3.png)