Oxymercuration-Demercuration Alkene Reaction Mechanism

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Oxymercuration-Demercuration, also referred to as oxymercuration-reduction is slightly more confusing than that average alkene reaction. I think it’s a combination of the extra steps, involvement of mercury, and the mysterious reduction by sodium borohydride. But don’t let this confuse you.

The video below takes you through the entire reaction mechanism with step by step explanations of every moving arrow, regioselectivity, and reason for lack of carbocation rearrangement.

Watch this video on YouTube or read the transcript (coming soon)

Watch the previous Video: Ring Expansion via Methyl and Hydride Shift

Watch Next video: Alkoxymercuration-demercuration

Return to: Alkene Reaction Mechanism home page;

Ready to test your skills? Click HERE for my FREE Alkene Reactions Practice Quiz


  1. At the end of step 2 do you still have acetic acid as a product? Or is that somehow used up during the reduction mechanism?

  2. how can mercury have a pair of electrons? i thought its electron configuration was [xe]4f14 5d10 6s2

    • This is a tricky concept Nick and I think the reason most professors skip it. Don’t forget that d-shell electrons are high in energy and may be called upon to react at any point in the mechanism.

  3. How can one compound be attached to two carbon atoms at same time ? Here HgOAc is attached to both primary and secondary?

  4. THANK YOU! I am in OChem 1 and have been struggling through the alkene reactions. You explain this so simply and give fantastic explanations for WHY the intermediates like HgOAc form the two bonds in the molecule. Thank you again!!

  5. dsrlington says:

    I cant play the video kindly send m link to the video

  6. You are my new favorite teacher! videos are clear and informative.

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