摘要
Stereoselective carbohydrate synthesis[1,2]has experiencedimmense strides in the last few years,benefiting from assimilatingknowledge at the frontiers of modern synthetic concepts.On thisfront,the dual but parallel development of radical catalysis in glycosylations[3–6]and the tapping of weak noncovalent interactions(NCIs)[7–11]for catalytic stereocontrol in stereoselective carbohydrate synthesis are of immense interest.It is important to emphasize that these two broad pillars were previously relativelyunheard of in thefield of classical carbohydrate chemistryfiveyears ago,but since then they have substantially established themselves in the mild and efficient construction of glycosidic linkages[12].The precise catalytic control of the stereochemistry of nativeglycosidic linkages had historically been challenging,as this seemingly simple C–O bond forming step required the concurrent tackling of two fundamental selectivity challenges(Fig.1a):Namelythe anomeric selectivity challenge to construct the C1 acetal andthe site-selectivity challenge[13,14]to discriminate the numeroushydroxyl groups on a carbohydrate polyol substrate.
