Use of iodine for efficient and chemoselective glycosylation with glycosyl ortho-alkynylbenzoates as donor in presence of thioglycosides

A novel and high yielding glycosylation protocol with glycosyl ortho-alkynylbenzoates as donors and iodine as promoter is described. The donors are stable and can be chemoselectively activated in the presence of thioethyl and thiophenyl glycosides. The application of this methodology in one-pot consecutive glycosylation reaction is described.