3,?5-?Di-?O-?benzyl-?1,?2-?O-?isopropylidene-?4-?C-?methanesulfonyloxyme?thyl-?α-?D-?ribofuranose is a reactant used in the preparation of abasic locked nucleic acid derivatives for stability analysis. Also used in the synthesis of oligonucleotides which contain novel thymidine moieties.