Return to Contents Chapter 16: Ethers, Epoxides and Sulfides Ch 16 contents

Cleavage of Ethers by HI or HBr

acid cleavage of ethers

Reaction type: Nucleophilic Substitution

Summary

QUESTIONS

 
  • If excess HBr is used, what would the products of the reaction be ?
  • ANSWER
     
  • Is the mechanism shown below SN1 or SN2 ?
  • ANSWER

    Related reactions

    MECHANISM FOR ACID CLEAVAGE OF ETHERS
    Step 1:
    An acid/base reaction. Protonation of the alcoholic oxygen to make a better leaving group. This step is very fast and reversible.  The lone pairs on the oxygen make it a Lewis base.
    HX ether cleaveage
    Step 2:
    The bromide ion functions as the nucleophile and attacks to displace the good leaving group, neutral alcohol molecule, by cleaving the C-O bond. This results in the formation of an alkyl bromide and an alcohol. 

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    © Dr. Ian Hunt, Department of Chemistry, University of Calgary