The Stereoselectivity of Neighboring Group-Directed Glycosylation Is Concentration-Dependent

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Фев. 5, 2025

The formation of 1,2-trans-glycosides taking advantage neighboring group participation by stereodirecting esters at the 2-position glycosyl donors is widely held to be a robust and reliable protocol. Examples abound, however, cases in which less-than-perfect selectivity obtained, causing practitioners survey different or resort alternative strategies quest for optimal selectivities yields. Consideration mechanism particular competing process SN2-like glycosylation with activated covalent leads hypothesis that imperfect selectivity, more careful attention reaction concentration stoichiometry may beneficial. Three case studies are presented demonstrate dependence group-directed reactions targeting both 1,2-trans-equatorial 1,2-trans-axial glycosides. Higher concentrations, whether achieved through increased acceptor:donor fixed stoichiometry, mostly lead erosion 1,2-trans-selectivity as becomes increasingly important. These observations underline importance rational, mechanism-based approach general importantly suggest simple enhancing displaying 1,2-trans-selectivity, namely, moving regime.

Язык: Английский

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Convergent Synthesis of Steviol Glycosides Rebaudioside A and M

Carbohydrate Research, Год журнала: 2025, Номер 552, С. 109446 - 109446

Опубликована: Март 6, 2025

Язык: Английский

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Bifunctional catalysts based on 2-amino-1,10-phenanthroline-containing podands for cyclic carbonates synthesis from CO2 and epoxides under mild conditions

Molecular Catalysis, Год журнала: 2025, Номер 579, С. 115019 - 115019

Опубликована: Март 22, 2025

Язык: Английский

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Organocatalyzed O-Glycosylation of Glycosyl Trichloroacetimidates Donors: L-Prolinethioamide as Brønsted Acid Catalyst

Carbohydrate Research, Год журнала: 2025, Номер unknown, С. 109470 - 109470

Опубликована: Март 1, 2025

Язык: Английский

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