Kinetically Controlled α-Selective O-Glycosylation of Phenol Derivatives Using 2-Nitroglycals by a Bifunctional Chiral Thiourea Catalyst

The highly α-selective organocatalytic glycosylation of phenol derivatives using 2-nitroglycals has been developed. The stereoselectivity of this reaction was kinetically controlled by a bifunctional thiourea catalyst, the chirality of which was crucial for obtaining the high α-selectivity. A variety of phenol derivatives were added to 2-nitrogalactal with excellent stereoselectivity. The reaction of 2-nitroglucal also achieved highly stereoselective glycosylation. The reaction was applied to the synthesis of glycopeptides.