Gold(I)-catalyzed synthesis of ß-Kdo glycosides using Kdo ortho-hexynylbenzoate as donor.

A gold(I)-catalyzed glycosylation of Kdo with glycosyl ortho-hexynylbenzoate as donor is reported. The couplings of Kdo ortho-hexynylbenzoate with a set of alcohols promoted by PPh3AuOTf afford Kdo glycosides with good ß-selectivities. This glycosylation method allows for the synthesis of ß-Kdo monosaccharide with a C5 linker at the reducing end for subsequent conjugation to carrier proteins and arrays.