5'-O-(4,4'-dimethoxytrityl)-2',3'-dideoxythymidine-3'-N-(2-oxo-4-spiro(pentamethylene-1,3,2-oxophospholane))

1-[(2R,4R,5R)-5-[Bis-(4-methoxy-phenyl)-phenyl-methoxymethyl]-4-(2-thioxo-3-oxa-1-thia-2λ5-phospha-spiro[4.5]dec-2-yloxy)-tetrahydro-furan-2-yl]-5-methyl-1H-pyrimidine-2,4-dione

5'-O-(4,4'-dimethoxytrityl)02',3'-dideoxythymidine-3'-N-(2-thio-4,4-spiro(pentamethylene-1,3,2-oxathiophospholane))

5’-O-DMT-N6-benzoyl-2’-deoxyadenosine-3’-O-(2-thio-4,4-pentamethylene-1,3,2-oxathiaphospholane)

5’-O-DMT-N2-isobutyryl-2’-deoxyguanosine-3’-O-(2-thio-4,4-pentamethylene-1,3,2-oxathiaphospholane)