Aglycon reactivity as a guiding principle in latent-active approach to chemical glycosylations

Photolabile 2-(2-Nitrophenyl)-propyloxycarbonyl (NPPOC) for Stereoselective Glycosylation and Its Application in Consecutive Assembly of Oligosaccharides

“…During the past decades, a variety of strategies have been developed to simplify or reduce the intermediate purification and thus streamline the chemical synthesis of oligosaccharides, including automated synthesis, one-pot glycosylation, poly­(tetrafluoroethylene) (PTFE)-assisted purification, and latent-active glycosylation . Given the superiority of the NPPPOC group in glycosylation and deprotection, we envision that a rapid assembly of oligosaccharides may be achieved without intermediate purification.…”

“…During the past decades, a variety of strategies have been developed to simplify or reduce the intermediate purification and thus streamline the chemical synthesis of oligosaccharides, including automated synthesis, 19 one-pot glycosylation, 20 poly(tetrafluoroethylene) (PTFE)-assisted purification, 21 and latent-active glycosylation. 22 Given the superiority of the NPPPOC group in glycosylation and deprotection, we envision that a rapid assembly of oligosaccharides may be achieved without intermediate purification. To demonstrate whether glycosylation could be influenced by 3, one of the major by-products isolated from the photolysis of the NPPOC group, glycosylation of acceptor A with donor 18, was carried out as a control experiment in the presence of 3 (Scheme 3A).…”

Stereoselective Synthesis of β-glycosyl Esters via 1-Hydroxybenzotriazole Mediated Acylation of Glycosyl Hemiacetals

“…Aromatic carboxylic acids with electron-withdrawing groups and/or electron-donating groups at various positions ( 3a – 3l ) were tolerated, delivering the desired β-glycosyl esters with 62% to 95% yields and almost complete stereocontrol. Notably, 2-iodobenzoate 3f which could be readily functionalized via cross-coupling reactions to enable latent-active glycosylation and ortho -alkynylbenzoates 3k and 3l capable of undergoing Au­(I)-catalyzed glycosylation − were efficiently synthesized. Gram-scale preparation of ortho -hexynylbenzoate 3k proceeded in 88% yield without loss of stereoselectivity (β/α > 19:1), testifying to the robustness and synthetic potential of this method.…”

S-o-(p-Methoxyphenylethynyl)benzyl (SMPEB) Glycosides for Catalytic Glycosylation and Their Application in the Synthesis of Polyporus Umbellatus Polysaccharides

“…Chemical synthesis is a reliable method to solve this bottleneck problem. To this end, a series of glycosylation methods, synthetic strategy, and purification means were explored to realize rapid preparation of saccharides. However, the key to the successful achievement of target saccharides relies on efficient installation of the desired glycosidic bonds.…”