Science of Synthesis

Nokami, T., Science of Synthesis Knowledge Updates, (2016) 2, 285.

Thioglycosides serve as glycosyl donors for the synthesis of ribonucleosides (‌Scheme 27‌).[‌33‌] Although the yield of nucleoside ‌63‌ is moderate, it takes only 10 minutes to complete the reaction in the presence of a stoichiometric amount of N-iodosuccinimide and trifluoromethanesulfonic acid. In contrast, N-glycosylation of silylated pyrimidines with S-arylthioglycosides in the presence of a catalytic amount of N-bromosuccinimide or bromine is carried out under electrochemical conditions (‌Scheme 28‌).[‌34‌] In this case, the supporting electrolyte tetrabutylammonium bromide is also effective as a mediator for anodic oxidation of thioglycosides. Electrochemical glycosylation of S-arylthioribofuranoside ‌64‌ with bis(trimethylsilyl)-5-fluorouracil ‌65‌ gives the β-nucleoside ‌66‌ in 85% yield.

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References