Effective One-pot Synthesis of H type 1 and 2 Trisaccharide Derivatives Using Glycal Epoxide

Abstract

We describe an efficient synthesis of H type 1 and 2 trisaccharides by one-pot glycosylation involving glycosidation of glycal epoxide.

Multi-Component One-Pot Synthesis of the Tumor-Associated Carbohydrate Antigen Globo-H Based on Preactivation of Thioglycosyl Donors

“…It was first assembled by Danishefsky and co-workers using the glycal strategy, , which was subsequently refined . Other elegant syntheses include Schmidt and Lassaletta's trichloroacetimidate method, Boon and Zhu's two-directional glycosylation, a reactivity based one-pot method by Wong and co-workers, − linear synthesis and automated solid-phase synthesis by the Seeberger group, as well as syntheses of the non-reducing end fragments. , However, many of the reported methods required various synthetic transformations of the oligosaccharide intermediates. Furthermore, with both α and β linkages in Globo-H, stereochemical control often became a formidable challenge. ,, Therefore, a highly efficient assembly of the Globo-H hexasaccharide is still in great demand.…”

Diversity-Oriented Enzymatic Modular Assembly of ABO Histo-blood Group Antigens

“…The biological significance and clinical importance of ABH antigens have ensured that their synthesis continues to be of significant interest for decades since the pioneering studies accomplished by Lemieux and co-workers in the 1970s . In the new millennium, many different approaches have been explored for the synthesis of ABH antigens, such as chemical synthesis, − chemoenzymatic synthesis, enzymatic synthesis, − and whole-cell fermentation . Despite the numerous synthetic approaches reported so far, the collective synthesis of all 15 naturally occurring ABH antigens has only been achieved through elegant chemical synthesis by Lowary and co-workers recently. − The non-natural type V ABH antigens were also chemically synthesized by the Lowary group …”

Chemical synthesis of the tumor-associated globo H antigen

“…The freed amino group and hydroxyl group were acetylated under routine conditions, which was followed by selective removal of the 2””- O -acetyl group with sodium methoxide in methanol to give 21 as a glycosyl acceptor. Finally, fucosylation of 21 with thioglycoside donor 4 26, 37 using NIS and TfOH as promoters resulted in stereospecific formation of the desired hexasaccharide 22 ( J H-Fuc-1,2 = 3.7 Hz) in a good yield (70%). We also transformed 4 into its corresponding trichloroacetimidate and tested it as a donor to react with acceptor 3 using TMSOTf as promotor; however, this reaction gave the desired hexasaccharide 22 in a very poor yield (15%).…”

“…16 Other elegant syntheses include Schmidt’s synthesis based on trichloroacetimidate glycosylation, 17 Boon’s synthesis employing a two-directional glycosylation strategy, 18 Wong’s reactivity based one-pot synthesis, 19, 20 Huang’s thioglycoside pre-activation based one-pot synthesis, 21 Wang’s enzymatic synthesis, 22 and Seeberger’s linear and solid-phase syntheses, 23, 24 as well as the synthesis of globo H fragments. 25, 26 In spite of the great progress in total synthesis of globo H, currently it is still difficult to access, especially in the form suitable for further elaborations, thus scientist has to rely on oneself to prepare it for any investigation. As a consequence, new synthetic strategies for globo H are still desirable.…”