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 degrees C) as well as the in situ trapping of the sulfenyl intermediate, which ensures that no homodimer of (RSH)-S-1 ((RSSR1)-S-1) 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. (C) 2010 Elsevier Ltd. All rights reserved.