Methanesulfonic acid (1S,3S)-1-(tert-butyl-dimethyl-silanyloxymethyl)-4,4,4-trifluoro-3-methanesulfonyloxymethyl-butyl ester

(2'R)-L-N4-benzoyl-5'-O-(tert-butyldimethylsilyl)-2',3'-dideoxy-2'-trifluoromethyl-4'-thiocytidine