Dual-Participation Protecting Group Solves the Anomeric Stereocontrol Problems in Glycosylation Reactions
Hui Liu1, Thomas Hansen2, Si-Yu Zhou1
1National Research Center for Carbohydrate Synthesis , Jiangxi Normal University , 99 Ziyang Avenue , Nanchang 330022 , China.
Abstract:
The 2,2-dimethyl-2-(ortho-nitrophenyl)acetyl (DMNPA) group permits, via robust neighboring group participation (NGP) or long distance participation (LDP) effects, the stereocontrolled 1,2-trans, 1,2-cis, as well as β-2,6-dideoxy glycosidic bond generation, while suppressing the undesired orthoester byproduct formation. The robust stereocontrol capability of the DMNPA is due to the dual-participation effect from both the ester functionality and the nitro group, verified by control reactions and DFT calculations and further corroborated by X-ray spectroscopy.
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