A high-yielding, one-pot preparation of unsymmetrical glycosyl disulfides using 1-chlorobenzotriazole as an in situ trapping/oxidizing agent

A high-yielding, one-pot methodology for preparing unsymmetrical glycosyl disulfides derived from sugar, alkyl/aryl or cysteine thiols is reported using 1-chlorobenzotriazole (BtCl) as the oxidant. The highlight of the method is the low temperature of coupling (−78 °C) as well as the in situ trapping of the sulfenyl intermediate, which ensures that no homodimer of R1SH (R1SSR1) is formed. The coupling efficiency is independent of sugar type, thiol position in the sugar, sugar-protecting groups, and the various products serve to illustrate the rapid synthetic access to a number of model systems in glycobiology.