Bis[3-(triethoxysilyl)propyl]tetrasulfide: the first liquid sulfur-transferring agent useful for conversion of nucleoside phosphites to the phosphorothioates

This paper describes bis[3-(triethoxysilyl)propyl]tetrasulfide, which is the first liquid sulfur-transferring agent useful for the conversion of nucleoside phosphite intermediates in the synthesis of the phosphorothioates using a phosphoramidite strategy. This liquid reagent is preferable to existing solid sulfur-transferring agents, because it enables solid-phase synthesis with an automated DNA/RNA synthesizer, while avoiding the risk of accumulation of reagent deposits in the delivery tubes and valves of the synthesizer during sulfurization.