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Palladium-Catalyzed ?-Stereoselective O-Glycosylation of O(3)-Acylated Glycals.

ABSTRACT: Pd(MeCN)2Cl2 enables the ?-stereoselective catalytic synthesis of 2,3-unsaturated O-glycosides from O(3)-acylated glycals without the requirement for additives to preactivate either donor or nucleophile. Mechanistic studies suggest that, unlike traditional (?3-allyl)palladium-mediated processes, the reaction proceeds via an alkoxy-palladium intermediate that increases the proton acidity and oxygen nucleophilicity of the alcohol. The method is exemplified with the synthesis of a range of glycosides and glycoconjugates of synthetic utility.

SUBMITTER: Sau A

PROVIDER: S-EPMC5479629 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

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Palladium-Catalyzed α-Stereoselective O-Glycosylation of O(3)-Acylated Glycals.

Sau Abhijit A Galan M Carmen MC

Organic letters 20170517 11

Pd(MeCN)<sub>2</sub>Cl<sub>2</sub> enables the α-stereoselective catalytic synthesis of 2,3-unsaturated O-glycosides from O(3)-acylated glycals without the requirement for additives to preactivate either donor or nucleophile. Mechanistic studies suggest that, unlike traditional (η3-allyl)palladium-mediated processes, the reaction proceeds via an alkoxy-palladium intermediate that increases the proton acidity and oxygen nucleophilicity of the alcohol. The method is exemplified with the synthesis ...[more]

PMID: 28514163

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