Chemical Synthesis of Furanose Glycosides

Abstract

Many bacterial, fungal, parasitical and plant species produce glycans containing O-furanoside linkages. These glycoconjugates are often essential for the viability of the organisms that produce them, and an increasing amount of work focused on their chemical synthesis has been carried out in recent years. However, despite these advances, compared to the synthesis of pyranose glycosides, this area has been poorly investigated. In this review we highlight the challenges inherent in the synthesis of furanose glycosides, summarize achievements in the field and suggest directions for future work.

Stereocontrolled Synthesis of α-Xylofuranosides Using a Conformationally Restricted Donor

“…1 , 2 Such species are most conveniently obtained by chemical synthesis, and over the past several years many methods for accessing furanose-containing glycans have been developed. 5 , 6 …”

“… 5 Consequently, the majority of robust methods for the stereocontrolled synthesis of 1,2- cis -furanosides employ conformationally locking groups resulting in a single energetically favored reaction pathway. 5 , 6 Such methods have previously been applied to the synthesis of β-arabinofuranosides ( 3 , Figure 1 B), 7 − 9 β-fructofuranosides ( 4 ), 10 and α-galactofuranosides ( 5 ). 11 − 13 …”

An ultra-low thiourea catalyzed strain-release glycosylation and a multicatalytic diversification strategy

“…The glycosyl donors employed in thiourea catalysis have remained in the pyranose realm and thiourea catalysis is rarely known to effectively catalyse glycosylations with donors bearing the furanose scaffold 33 – 36 . In fact, effective furanosylation protocols are scarce in catalysis 34 – 36 . This is a fundamental synthetic gap since furanosides are highly prevalent in nature and are ubiquitous in the ribose-phosphate backbones of nucleic acids such as DNA, RNA, and signaling molecules such as ATP.…”

Pyranoside‐into‐Furanoside Rearrangement: New Reaction in Carbohydrate Chemistry and Its Application in Oligosaccharide Synthesis

“…[3][4][5][6] Currently, the most widely used methods for furanoside synthesis are based on the initial transformation of unblocked monosaccharides by the Fischer reaction under kinetic control [7,8] or their high-temperature acylation. [7,9] All of these reactions proceed with the formation of a mixture of aand b-furanosides and are contaminated by re-spective pyranoside isomers that may require laborious chromatography in order to separate the target products. It is also notable that further regioselective introduction of O-blocking groups into furanosides can be more difficult than in the case of related pyranoside derivatives.…”