Fig. 2. S-phenyl donors equipped with ester protection groups on systematically varied positions on the ring.

a Glycosyl donors used for IRIS experiments and DFT computations. Donors 3–9 and 13–15 were converted into their corresponding sulfoxides prior for the IRIS experiments to improve the yield of the glycosyl cation generation³³. b Glycosyl donors used for chemical glycosylation reaction in solution.