Synthesis of pentaarabinofuranosyl structure motif A of Mycobacterium tuberculosis
作者:Hari Babu Mereyala、Srinivas Hotha、Mukund K. Gurjar
DOI:10.1039/a707796c
日期:——
The first synthesis of motif A, the branched chain arabinofuranosyl pentasaccharide [t-β-Araf-(1 → 2)-α-D-Araf]2-3,5-α-D-Araf-(1 → 5) which constitutes the major humoral immunological epitope in the arabinogalactan cell wall of Mycobacterium tuberculosis is described.
their significance in controlling disease spurred interest in developing strategies for their diastereoselective synthesis. Mtb uses enzymes to achieve diastereoselectivity through noncovalent interactions. Of the two possible glycosidic linkages, chemically, 1,2-trans linkage is relatively easy to synthesize by taking advantage of neighboringgroupparticipation, whereas synthesis of the 1,2-cis linkage
Samarium Diiodide Mediated Coupling of 2-Pyridylsulfonyl Furanosides with Aldehydes and Ketones: A General Synthesis of<i>C</i>-Furanosides
作者:Jin Wang、Fabien Gasc、Jacques Prandi
DOI:10.1002/ejoc.201403640
日期:2015.4
Diiodosamarium-mediated coupling of anomeric 2-pyridyl sulfones derived from furanosides with carbonyl compounds, aldehydes, and ketones gave α-hydroxylated 2,5-trans-dialkylated tetrahydrofurans with good yields and useful stereoselectivities. The main control element of the reaction is the substituent on the 4-position or the starting furanosyl sulfone. C-Furanosides of D-arabinose and of D-ribose
heteroaryl glycosyl sulfones undergo desulfonylative C−C cross-coupling with aryl-substituted nucleophiles or electrophiles through two complementary catalytic systems. The reactions offer access to a wide variety of C-aryl glycoside products with high diastereoselectivity.
A Glycosylation Protocol Based on Activation of Glycosyl 2-Pyridyl Sulfones with Samarium Triflate
作者:Grace X. Chang、Todd L. Lowary
DOI:10.1021/ol005579k
日期:2000.6.1
[reaction--see text] Reaction of glycosyl 2-pridyl sulfones (e.g.,2) with alcohols and samarium(III) triflate affords glycosides in moderate to excellent yields. Benzylated sulfones can be activated in preference to their benzoylated counterparts, and the methodology has been used to prepare di- and trisaccharides containing both furanose and pyranose residues. Thioglycosides do not react under these