Gold(I)-Catalyzed Direct Stereoselective Synthesis of Deoxyglycosides from Glycals
作者:Carlos Palo-Nieto、Abhijit Sau、M. Carmen Galan
DOI:10.1021/jacs.7b08898
日期:2017.10.11
AgOTf enables the unprecedented direct and α-stereoselective catalytic synthesis of deoxyglycosides fromglycals. Mechanistic investigations suggest that the reaction proceeds via Au(I)-catalyzed hydrofunctionalization of the enol ether glycoside. The room temperature reaction is high yielding and amenable to a wide range of glycal donors and OH nucleophiles.
Copper Reactivity Can Be Tuned to Catalyze the Stereoselective Synthesis of 2-Deoxyglycosides from Glycals
作者:Carlos Palo-Nieto、Abhijit Sau、Robin Jeanneret、Pierre-Adrien Payard、Aude Salamé、Maristela Braga Martins-Teixeira、Ivone Carvalho、Laurence Grimaud、M. Carmen Galan
DOI:10.1021/acs.orglett.9b04525
日期:2020.3.6
We demonstrate that tuning the reactivity of Cu by the choice of oxidation state and counterion leads to the activation of both "armed" and "disarmed" type glycals toward direct glycosylation leading to the α-stereoselective synthesis of deoxyglycosides in good to excellent yields. Mechanistic studies show that CuI is essential for effective catalysis and stereocontrol and that the reaction proceeds
Substrate-Controlled Direct α-Stereoselective Synthesis of Deoxyglycosides from Glycals Using B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> as Catalyst
作者:Abhijit Sau、Carlos Palo-Nieto、M. Carmen Galan
DOI:10.1021/acs.joc.8b02613
日期:2019.3.1
α-stereoselective synthesis of deoxyglycosides fromglycals. 2,3-Unsaturated α- O-glycoside products are obtained with deactivated glycals at 75 °C in the presence of the catalyst, while 2-deoxyglycosides are formed using activated glycals that bear no leaving group at C-3 at lower temperatures. The reaction proceeds in good to excellent yields via concomitant borane activation of glycal donor and nucleophile
Palladium‐Catalyzed Direct Stereoselective Synthesis of Deoxyglycosides from Glycals
作者:Abhijit Sau、Ryan Williams、Carlos Palo‐Nieto、Antonio Franconetti、Sandra Medina、M. Carmen Galan
DOI:10.1002/anie.201612071
日期:2017.3.20
in combination with a monodentate phosphine ligand enables the unprecedented direct and α‐stereoselective catalytic synthesis of deoxyglycosides from glycals. Initial mechanistic studies suggest that in the presence of N‐phenyl‐2‐(di‐tert‐butylphosphino)pyrrole as the ligand, the reaction proceeds via an alkoxy palladium intermediate that increases the proton acidity and oxygen nucleophilicity of the
Regioselective direct sulfenylation of glycals using arylsulfonyl chlorides in the presence of triphenylphosphine: access to C2-thioaryl glycosides
作者:Harikesh Kumar、Atul Dubey、Gurudayal Prajapati、Ruchir Kant、Ravi S. Ampapathi、Pintu Kumar Mandal
DOI:10.1039/d1nj05228d
日期:——
Direct triphenylphosphine-mediated regioselective sulfenylation of glycals by using various cheap and easily available aryl sulfonyl chlorides as a sulfur source to generate different C2-S-aryl-glycosides was developed. Notably, the features of this protocol offer a milder and easier operational procedure, and broad substrate scope with complete regioselectivity at C-2. Experiments and DFT calculations