3',5'-O-di-tert-butyldimethylsilyl-2-N-(p-iodobenzyl)-2'-deoxyguanosine

O6-benzyl-2-chloro-3',5'-bis-O-(tert-butyldimethylsilyl)-2'-deoxyguanosine

2-amino-9-(3,5-di-O-tert-butyldimethylsilyl-2-deoxy-β-D-ribofuranosyl)-6-(1-propenyl)purine

5'-O-3'-O-bis(tert-butyldimethylsilyl)-6-O-benzyl-2-N-benzyl-2'-deoxyguanosine

{6-Benzyloxy-9-[(2R,4S,5R)-4-(tert-butyl-dimethyl-silanyloxy)-5-(tert-butyl-dimethyl-silanyloxymethyl)-tetrahydro-furan-2-yl]-9H-purin-2-yl}-carbamic acid benzyl ester