Stereoselective O-Glycosylation of Glycals with Arylboronic Acids Using Air as the Oxygen Source
Qiuyuan Wang, Mengnan Lai, Huajun Luo, Keke Ren, Jingrui Wang, Nianyu Huang, Zhangshuang Deng, Kun Zou, Hui Yao
Abstract
An open-air palladium-catalyzed O-glycosylation was developed using glycals and arylboronic acids with base additives at ambient conditions. The novel approach enabled facile access to various O-glycosides in high yields, with exclusive 1,4-cis-stereoselectivity tolerating reactive hydroxyl/amino groups. Mechanistic studies indicated that chemo-/stereoselectivity arose from the coordination between palladium and phenols generated in situ by oxidizing arylboronic acids, followed by an intramolecular attack. Isotope-labeling experiments revealed that the oxygen of O-glycosidic bonds came from O2.
Topics & Concepts
ChemistryStereoselectivityGlycosidic bondOxidizing agentIntramolecular forceGlycosylationPalladiumCatalysisOrganic chemistryCombinatorial chemistryBiochemistryEnzymeCarbohydrate Chemistry and SynthesisGlycosylation and Glycoproteins ResearchChemical Synthesis and Analysis