Highly Stereoselective 1,2-cis-Xylosylation Enabled by Reagent Modulation, Remote Participation, and
Jie Wan1, Yujie Ji2, Leilei Wang1
1State Key Laboratory of Phytochemistry and Natural Medicines, Kunming Institute of Botany, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, 650201, China.
Abstract:
Stereoselective constructions of 1,2-cis-glycosidic bonds are long-standing challenges in chemical synthesis. In particular, achieving highly stereoselective 1,2-cis-xylosylation remains a difficult task in carbohydrates chemistry. Here, we report that highly stereoselective 1,2-cis-xylosylation could be achieved via synergistic combinations of reagent modulation, remote participation, and electron-withdrawing effects. A variety of α-xylosides motifs have been effectively prepared by this 1,2-cis-xylosylation protocol, including hemicellulose xyloglucan, xyloglucosyl trisaccharide motif from mammalian cells, core M3 matriglycan motif, and even α-(1→3)-xylosides up to 12-mer. Furthermore, DFT calculations provided the origins of this stereoselective and synergistic 1,2-cis-xylosylation through SN1 and SN2 pathways.
More Related Videos
07:36Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
Published on: November 9, 2019
08:46Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides
Published on: July 26, 2018
Related Concept Videos
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
02:23SN2 Reaction: Stereochemistry
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not...
03:00Preparation of Epoxides
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of...
02:36Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
01:28Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
01:26Thermal and Photochemical Electrocyclic Reactions: Overview