5'-{3-[(3'R)-5'-(4,4'-Dimethoxytrityl)-3'-deoxythymidin-3'-yl]-2-oxopropyl}-5'-deoxythymidine

3'-O-Acetyl-5'-{3-[(3'R)-5'-(4,4'-dimethoxytrityl)-3'-deoxythymidin-3'-yl]-2-oxopropyl}-5'-deoxythymidine

2-Cyanoethyl {5'-[3-((3'R)-3'-deoxythymidin-3'-yl)-2-oxopropyl]-5'-deoxythymidin-3'-yl}(3'-acetylthymidin-5'-O-yl)phosphinate

5'-{3-[(3'R)-5'-(4,4'-Dimethoxytrityl)-3'-deoxythymidin-3'-yl]-2-oxopropyl}-3'-O-[2-cyanoethoxy(diisopropylamino)phosphino]-5'-deoxythymidine

{(2S,3R,5R)-2-(tert-Butyl-dimethyl-silanyloxymethyl)-5-[5-methyl-2,4-dioxo-3-(2-trimethylsilanyl-ethoxymethyl)-3,4-dihydro-2H-pyrimidin-1-yl]-tetrahydro-furan-3-yl}-acetaldehyde