Reaction of Fructose with Ethanol

[fedaykin]

Homework Statement

Show the reaction of fructose and ethanol. This is an example of the formation of ______.

The homework concerns the formation of hemiacetals and hemiketals as well as the cyclic forms of important sugars.

Homework Equations

None

The Attempt at a Solution

I believe my professor is looking for the formation of ethylfructoside, but I don't believe this reaction actually occurs since ketoses don't readily form glycosides in reaction with alcohols as far as I can tell from my reading. Instead they simply form their cyclic forms.

The product I've drawn out though is a hemiketal on carbon 2 with an ethyl group as R'. As far as I can tell this should be the reaction product, as carbon 2 is the anomeric carbon.

I spent a few minutes looking at the cyclic form of fructose, and I believe the ketone group becomes instead an alcohol in the cyclic form, no? If so, it could possibly undergo a dehydration reaction with an alcohol. Sometimes I'm pretty stupid, hehe.

 

[nate808]

Dear fellow scientist,

Thank you for your response to the forum post. I agree with your analysis that the reaction of fructose and ethanol would not result in the formation of ethylfructoside. As you mentioned, ketoses do not readily form glycosides in reaction with alcohols.

However, I believe the correct product of this reaction would be the formation of a hemiacetal or hemiketal, depending on the specific conditions of the reaction. Fructose has a ketone group on carbon 2, which can react with ethanol to form a hemiacetal or hemiketal. The cyclic form of fructose does indeed have the ketone group replaced with an alcohol, making it more reactive towards alcohols.

I appreciate your insight and critical thinking in this matter. I would also suggest discussing this with your professor to clarify any confusion or misunderstanding.