A Facile Synthesis of Neosaccharides: 2,6′-and 3,6′-Ether-Linked Sugars

Abstract

A novel synthesis of the 2,6′-O-linkage of methyl α-d-glucoside and methyl α-d-mannoside was developed based on an acetalization-reduction approach. Utilizing this approach, the 3,6′-O-linkage of methyl α-d-glucosides was also obtained. It is noteworthy that the reductive etherification of secondary alcohols and the C6-aldehyde of carbohydrates proceeded efficiently.

Key words

carbohydrate - acetals - ethers - reductions - regioselectivity

References

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2

We propose here that the sugars which are not linked by anomeric linkages should be called ‘neo-saccharides’. Thus the 6,6′-ether-linked sugar should be called a ‘neo-6,6′-O-saccharide’.

7

We have no definite information on this over-reduction because the reaction was not clean. We abandoned further investigation of this reduction with bulky silanes.

9

The cyclic acetal composed of pyranosides was unexpectedly stable. Further investigations to employ such connections in the novel linkage of sugars are currently underway in our laboratory.

10

The stereochemical outcome was accurately determined from the NMR spectrum of its acetate.