N2-(2-amino-9H-fluoren-3-yl)-3',5'-bis-O-(tert-butyldimethylsilyl)-2'-deoxyguanosine

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

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

N2-(2-acetylamino-5-(phenyl)phenyl)-3',5'-bis-O-(tert-butyldimethylsilyl)-2'-deoxyguanosine

7-{6-benzyloxy-9-[4-(tert-butyldimethylsilyloxy)-5-(tert-butyldimethylsilyloxymethyl)-tetrahydrofuran-2-yl]-9H-purin-2-ylamino}-6-(tert-butyldimethylsilyloxymethyl)-6H-benzo[f][1,3]dioxolo[4',5':4,5]benzo[1,2,3-cd]indol-5-one