Synthesis of 4'-substituted cordycepins.

Synthesis of 4'-substituted analogues of cordycepin was carried out. Electrophilic addition of N-iodosuccinimide/benzoic acid to 2',5'-bis-O-(tert-butyldimethyl-silyl)-3',4'-unsaturated adenosine (5) enabled the introduction of a leaving group to the 4'-position. The resulting product 7 was converted to 4'-(benzoyloxy) cordycepin (8) upon removal of the 3'-iodine atom. Compound 8 serves as a common precursor for the synthesis of the title compounds through nucleophilic substitution using organoaluminum and organosilicon reagents.