67145-38-4Relevant articles and documents
Synthesis of blood group A and B (type 2) tetrasaccharides. A strategy with fucosylation at the last stage
Kunetskiy, Roman A.,Pazynina, Galina V.,Ivanov, Igor A.,Bovin, Nicolai V.
, (2020)
The traditionally used strategy for the synthesis of blood group A and B tetrasaccharides includes 2′-O-fucosylation of lactosamine followed by insertion of an α1-3 linked N-acetylgalactosamine or a galactose moiety. Here, we report the synthesis of 3-aminopropyl glycosides of A (type 2) and B (type 2) tetrasaccharides via an alternative sequence, i.e. α-galactosaminylation (or α-galactosylation) followed by α-fucosylation. This strategy allows us to synthesize fucose-free trisaccharides GalNAcα1-3Galβ1-4GlcNAc and Galα1-3Galβ1-4GlcNAc, which are promising targets for immunotherapy utilising human natural antibodies against the trisaccharides. The key stage in this scheme was the selective chloroacetylation of the 2′-OH group of βGal in the intermediate trisaccharides having the second (3-OH) unprotected group.The protocol is suitable for multigram syntheses and its further scaling up.
Stereocontrolled α-Galactosylation under Cooperative Catalysis
Shadrick, Melanie,Singh, Yashapal,Demchenko, Alexei V.
, p. 15936 - 15944 (2020/11/20)
A recent discovery of a cooperative catalysis comprising a silver salt and an acid led to a dramatic improvement in the way glycosyl halides are glycosidated. Excellent yields have been achieved, but the stereoselectivity achieved with 2-O-benzylated donors was poor. Reported herein is our first attempt to refine the stereoselectivity of the cooperatively catalyzed galactosylation reaction. Careful optimization of the reaction conditions along with studying effects of the remote protecting groups led to excellent stereocontrol of α-galactosylation of a variety of glycosyl acceptors with differentially protected galactosyl donors.
Koenigs–Knorr Glycosylation Reaction Catalyzed by Trimethylsilyl Trifluoromethanesulfonate
Singh, Yashapal,Demchenko, Alexei V.
supporting information, p. 1461 - 1465 (2019/01/04)
The discovery that traditional silver(I)-oxide-promoted glycosidations of glycosyl bromides (Koenigs–Knorr reaction) can be greatly accelerated in the presence of catalytic trimethylsilyl trifluoromethanesulfonate (TMSOTf) is reported. The reaction conditions are very mild that allowed for maintaining a practically neutral pH and, at the same time, providing high rates and excellent glycosylation yields. In addition, unusual reactivity trends among a series of differentially protected glycosyl bromides were documented. In particular, benzoylated α-bromides were much more reactive than their benzylated counterparts under these conditions.
