Explaining Mechanism of Glucose Pentaacetate Reaction

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SUMMARY

The reaction of glucose (C6H12O6) with acetyl chloride (CH3COCl) produces glucose pentaacetate (CHO(CHOOCCH3)4CH2OOCCH3) through a nucleophilic acyl substitution mechanism. The acetyl chloride dissociates into a positively charged acetyl cation (CH3C+) and a chloride ion (Cl-), which then reacts with the hydroxyl (OH) groups of glucose. The formation of the O-O bond in glucose pentaacetate is clarified as a representation issue, where -OOC- indicates a carbon double-bonded to one oxygen and singly bonded to another, rather than a direct O-O bond. The discussion emphasizes the preference for nucleophilic attack over the formation of an acylium ion due to stability concerns regarding the ion pair intermediate.

PREREQUISITES
  • Understanding of nucleophilic acyl substitution reactions
  • Familiarity with organic chemistry functional groups, specifically hydroxyl and acyl groups
  • Knowledge of glucose structure and its reactivity
  • Basic concepts of reaction mechanisms in organic chemistry
NEXT STEPS
  • Study the mechanism of nucleophilic acyl substitution in detail
  • Explore the structural representation of glucose derivatives and their implications
  • Research the stability of ion pair intermediates in organic reactions
  • Learn about the role of Lewis acids like FeCl3 and AlCl3 in facilitating reactions
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Chemistry students, organic chemists, and anyone interested in reaction mechanisms involving carbohydrates and acyl chlorides.

nil1996
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Homework Statement



can anybody explain the mechanism of the reaction



C6H12O6 +CH3COCl → CHO(CHOOCCH3)4CH2OOCCH3

glucose + acetyl chloride → glucose pentaacetate

Homework Equations



none

The Attempt at a Solution


I am thinking that the CH3COCl will split as CH3C+O and Cl-.
Now these positively charged group will react with the five OH groups by displacing the hydrogens.

But i am not understanding how there is bond between O-O in glucose pentaacetate (which doesn't fit in my above mechanism.)
 
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This is just a limitation of linear representation of the structure. -OOC- does not mean a O-O bond, rather a carbon double bonded to an oxygen, and also singly bonded to a different oxygen.
 
Then is the mechanism correct?
 
I'd prefer nucleophilic attack on the acid chloride, rather than the acylium ion you have proposed.
 
can you explain why you are preferring the nucleophile attack?
 
I don't think the ion pair intermediate you've proposed is that stable, though I believe similar do exist in the presence of things like Fe or Al chlorides
 

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