Highly stereoselective synthesis of 2-azido-2-deoxyglucosides and 2-azido-2-deoxygalactosides is achieved via a gold-catalyzed S_(N)2 glycosylation.The glycosyl donors feature a designed 1-naphthoate leaving group con...Highly stereoselective synthesis of 2-azido-2-deoxyglucosides and 2-azido-2-deoxygalactosides is achieved via a gold-catalyzed S_(N)2 glycosylation.The glycosyl donors feature a designed 1-naphthoate leaving group containing an amide group.Upon gold activation of the leaving group,the amide group is optimally positioned to direct an S_(N)2 attack by an acceptor via H-bonding interaction.Both 2-azido-2-deoxyglucosyl/galactosyl donor anomers can undergo stereoinversion at the anomeric position,affording the opposite anomeric glycoside products with excellent levels of stereoselectivity or stereospecificity and in mostly excellent yields.This S_(N)2 glycosylation accommodates a broad range of acceptors.The utility of this chemistry is demonstrated in the synthesis of a trisaccharide featuring three 1,2-cis-2-azido-2-deoxyglycosidic linkages.展开更多
基金Supported by National Natural Science Foundation of China(No.30870506,No.31070724)Qingdao Science and Technology Project(No.11-2-2-1-hy)Public Science and Technology Research Funds Projects of Ocean(No.201005024)~~
基金the National Institutes of Health(grant nos.U01GM125289 and R35GM139640)for financial supportthe National Science Foundation(grant no.MRI-1920299)for the acquisition of two Bruker NMR instruments.
文摘Highly stereoselective synthesis of 2-azido-2-deoxyglucosides and 2-azido-2-deoxygalactosides is achieved via a gold-catalyzed S_(N)2 glycosylation.The glycosyl donors feature a designed 1-naphthoate leaving group containing an amide group.Upon gold activation of the leaving group,the amide group is optimally positioned to direct an S_(N)2 attack by an acceptor via H-bonding interaction.Both 2-azido-2-deoxyglucosyl/galactosyl donor anomers can undergo stereoinversion at the anomeric position,affording the opposite anomeric glycoside products with excellent levels of stereoselectivity or stereospecificity and in mostly excellent yields.This S_(N)2 glycosylation accommodates a broad range of acceptors.The utility of this chemistry is demonstrated in the synthesis of a trisaccharide featuring three 1,2-cis-2-azido-2-deoxyglycosidic linkages.