Additive‐Free Gold(III)‐Catalyzed Stereoselective Synthesis of 2‐Deoxyglycosides Using Phenylpropiolate Glycosides as Donors
作者:Mukta Shaw、Amit Kumar
DOI:10.1002/asia.201900888
日期:2019.12.13
Stereoselectivesynthesis of deoxyglycosides has been achieved from benchtop stable and easily synthesizable deoxy-phenylpropiolate glycosides (D-PPGs) using gold(III) salt as catalyst under external additive-free conditions. Under a simple catalytic system, D-PPGs reacted with a variety of sugar and non-sugar acceptors to produce majorly α-stereoselective O/N-deoxyglycosides in good to excellent yields
作者:Yongho Park、Kaid C. Harper、Nadine Kuhl、Eugene E. Kwan、Richard Y. Liu、Eric N. Jacobsen
DOI:10.1126/science.aal1875
日期:2017.1.13
challenges to their synthesis. In particular, stereochemical outcomes in glycosylationreactions are highly dependent on the steric and electronic properties of coupling partners; thus, carbohydrate synthesis is not easily predictable. Here we report the discovery of a macrocyclic bis-thiourea derivative that catalyzes stereospecific invertive substitution pathways of glycosyl chlorides. The utility of
Stereoselective synthesis of α-linked 2-deoxysaccharides and furanosaccharides by use of 2-deoxy 2-pyridyl-1-thio pyrano- and furanosides as donors and methyl iodide as an activator
A practical and highly stereoselective glycosidation methodology is described, where anomeric mixture of 2-deoxy 2-pyridyl-1-thiopyranoside donors (1–3, 27) have been coupled with several sugar alcohols (4–8,29,31) on activation by methyl iodide to obtain axiallylinked2-deoxysaccharides (9–17,30,32,33). Application of this method for the synthesis of disaccharide fragment 28 of avermectin is also
Visible Light Mediated Activation and <i>O-</i>Glycosylation of Thioglycosides
作者:Walter J. Wever、Maris A. Cinelli、Albert A. Bowers
DOI:10.1021/ol302941q
日期:2013.1.4
Visible light catalysis allows the efficient construction of single electron transfer (SET) redox cycles that result in minimal formation of byproducts and proceed under exogenous control of a removable light source. The O-glycosylation of thioglycosides via visible light photoredox chemistry is reported. Mechanistic studies show that the reaction is fully light responsive and support a mechanism involving decomposition of an oxidatively generated sulfur radical cation and propagation via reduction of the thiol side product.