I’m quite confused about whether glycosidic linkages can be considered being ether bonds or not. My textbook has this written in the Carbohydrates chapter:

It is possible for a sugar hydroxyl group ($\ce{ROH}$) bonded to the anomeric carbon to react with another hydroxyl ($\ce{R'OH}$) to form a glycosidic linkage ($\ce{R'-O-R}$). A glycosidic linkage is not an ether (the $\ce{R'-O-R}$ notation is mis- leading) because glycosides can be hydrolyzed to the original alcohols. This type of reaction involves the anomeric carbon of the sugar in its cyclic form. (Recall that the anomeric carbon is the carbonyl carbon of the open-chain form of the sugar and is the one that becomes a chiral center in the cyclic form.) Stated in a slightly different way, a hemiacetal carbon can react with an alcohol such as methyl alcohol to give a full acetal, or glycoside.

Biochemistry by Mary K. Campbell and Shawn O. Farrell, Brooks Cole; 7th edition

On the other hand, a simple search on Google says that glycosidic bonds are indeed ethers, an extract from study.com is shown below:

The result of a glycosidic bond is a sugar molecule linked to another molecule via an ether group. An ether is an oxygen atom bonded to two carbon atoms, which is relatively unreactive compared to other chemical groups, such as alcohols. Therefore, glycosides tend to be more stable than free sugars.

Can you please explain the discrepancy in the information?

  • 1
    $\begingroup$ Your text has it right; ignore Wikipedia. R'-O-R is not the same as R'-O-CHR-OR''. The former is a "true" ether while the latter is an acetal, which is more labile to acid hydrolysis than most standard ethers such as diethyl ether. $\endgroup$
    – user55119
    Aug 2 at 17:12


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