N-Heterocyclic Carbene Catalyzed C-Glycosylation: A Concise Approach from Stetter Reaction

Abstract

Described herein is the first example of an organocatalytic approach for acylanion addition to the anomeric carbon of 2-nitroglucal using an N-heterocyclic carbene catalyst. Control over the reaction conditions gives β-selective and nitro-eliminated C-glycosides, providing opportunities to produce new classes of C-glycoside.

Organocatalytic Reactions Enabled by N-Heterocyclic Carbenes

“…102 Two products are observed, which could each be isolated in good yield by judicious selection of the reaction conditions (Scheme 38). The use of amine bases leads to the Stetter reaction, while an excess of stronger carbonate bases results in elimination of nitrous acid, forming the corresponding enone.…”

Electron-deficient pyridinium salts/thiourea cooperative catalyzed O-glycosylation via activation of O-glycosyl trichloroacetimidate donors

“…Taking inspiration from nature, in the last few decades chemists around the world have utilized organic molecules to accelerate many imperative organic transformations [14–17]. One of the major applications of organocatalysis lies in the field of enantioselective synthesis, where organocatalysts are considered as fundamental tools in the catalysis toolbox [18–22].…”

Organocatalyzed Glycosylation Reactions of Carbohydrates

“…The authors describe an acylanion addition to protected 2-nitroglycals Scheme 4.6 Thiourea-catalyzed glycosylation of glycals in the presence of N-hetereocyclic carbene catalyst 23 (Scheme 4.9) [70]. This approach yields a stereoselective access to C-glycosides, providing the opportunity to produce new classes of C-glycosides.…”