Synthesis of a 3′-Deoxy-C-Nucleoside Phosphonate Bearing 9-Deazaadenine as Base Moiety

Herein, the synthesis of the first example of a 3′-deoxy-5′-phosphonate 2′[R] C-nucleoside and its corresponding prodrug is presented. The developed route involves a reductive debromination at the 2′-position of a suitably substituted 9-deazaadenosine intermediate, followed by a stereoselective glycosylation at the 5′-anomeric position to achieve the installation of the phosphonomethoxy functionality. The target compound with the desired configuration is formed upon base-promoted epimerization at the 2′[S]-position of the sugar moiety.