Selective synthesis of a novel methylenecyclobutane nucleoside analogue

Nucleophilic ring-opening of the unsymmetrical cyclobutyl epoxide 10a by ad enine yielded a mixture of three nucleoside compounds 9a-c. Their structure s have been elucidated with the aid of various NMR techniques, in particula r by heteronuclear multiple bond correlation (HMBC). The major isomer was s electively benzylated at the secondary hydroxyl group to afford 13. Subsequ ent mesylation of the hydroxymethyl group, followed by conversion into an o -nitrophenylselenide and oxidation yielded the elimination product 16. Depr otection with boron trichloride provided the novel methyl-enecyclobutane nu cleoside analogue 8.