Effective Synthesis of α‐d‐GlcN‐(1→4)‐d‐GlcA/l‐IdoA Glycosidic Linkage under Gold(I) Catalysis. Issue 8 (29th May 2015)

• Record Type: Journal Article
• Authors: Li, Jiakun; Dai, Yuanwei; Li, Wei; Laval, Stéphane; Xu, Peng; Yu, Biao
• Is Part Of: Asian journal of organic chemistry. Volume 4:Issue 8(2015:Aug.)
• Page Start: 756
• Page End: 762
• Publication Date: 2015-05-29
• Subjects: Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; 547.005
• DOI: 10.1002/ajoc.201500113
• Languages: English
• ISSNs: 2193-5807

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>An effective glycosylation procedure for the stereoselective construction of the α‐<sc>d</sc>‐GlcN‐(1→4)‐<sc>d</sc>‐GlcA/<sc>l</sc>‐IdoA glycosidic linkage found in heparin and heparan sulfate is reported. The condensation occurs between 2‐deoxy‐2‐azido‐<sc>d</sc>‐glucopyranosyl (<sc>d</sc>‐GlcN) <italic>ortho</italic>‐hexynylbenzoate donors and uronate acceptors (<sc>d</sc>‐GlcA/<sc>l</sc>‐IdoA) under mild gold(I)‐catalyzed conditions. Optimal results are obtained when performing the reaction in CH₂Cl₂, from −72 °C to room temperature in the presence of 4 Å molecular sieves and under the promotion of [Ph₃PAuCl]/AgOTf or [(1, 1‐bis‐(diphenylphosphino)methane)(AuCl)₂]/AgOTf as a source of the gold(I) catalyst. A donor/acceptor ratio of 3:1 as well as a loading of 0.6 equivalents of the gold(I) catalyst are essential to attain high yields and α selectivity, particularly for the [1+1] and [1+2] glycosylations.</p> </abstract>