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
Stereoselective organocatalyzed glycosylations – thiouracil, thioureas and monothiophthalimide act as Brønsted acid catalysts at low loadings
作者:G. A. Bradshaw、A. C. Colgan、N. P. Allen、I. Pongener、M. B. Boland、Y. Ortin、E. M. McGarrigle
DOI:10.1039/c8sc02788a
日期:——
Thiouracil catalyzes stereoselective glycosylations with galactals in loadings as low as 0.1 mol%.
硫尿嘧啶在载体负载量低至0.1 mol%时,催化与半乳糖醛糖苷的立体选择性糖基化。
Cooperative Brønsted Acid-Type Organocatalysis for the Stereoselective Synthesis of Deoxyglycosides
作者:Carlos Palo-Nieto、Abhijit Sau、Ryan Williams、M. Carmen Galan
DOI:10.1021/acs.joc.6b02498
日期:2017.1.6
α-stereoselective synthesis of deoxyglycosides using cooperative Brønsted acid-type organocatalysis has been developed. The method is tolerant of a wide range of glycoside donors and acceptors, and its versatility is exemplified in the one-pot synthesis of a trisaccharide. Mechanistic studies suggest that thiourea-induced acid amplification of the chiral acid via H-bonding is key for the enhancement
devised a method for stereoselective O-glycosylation using an Ir(I)-catalyst which enables both hydroalkoxylation and nucleophilic substitution of glycals with varying substituents at the C3 position. In this transformation, 2-deoxy-α-O-glycosides were acquired when glycals equipped with a notoriously poor leaving group at C3 were used; in contrast 2,3-unsaturated-α-O-glycosides were produced from glycals