April 29, 2024, 10:54:25 AM
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Topic: Sonogashira Coupling hydroxy group removal Mechanism  (Read 532 times)

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Offline emmazola

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Sonogashira Coupling hydroxy group removal Mechanism
« on: January 08, 2024, 12:32:48 PM »
Hi all,
I am currently writing my report and had to answer the question: The alkyne was chosen as the hydroxy isopropyl group can be easily removed, as shown in the scheme below, permitting further coupling reactions to take place. Draw a mechanism to show how this might occur, take into account the pKa of an alkyne.
I was unsure on the mechanism for this so drafted one up in ChemDraw, could anyone please look over this and comment on its validity? Many thanks!

Offline Babcock_Hall

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Re: Sonogashira Coupling hydroxy group removal Mechanism
« Reply #1 on: January 08, 2024, 01:55:06 PM »
I see a number of things that strike me as debatable.  The one that jumped out was that you have a hydride ion attacking an electron-rich position near the end of the mechanism.

Offline rolnor

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Re: Sonogashira Coupling hydroxy group removal Mechanism
« Reply #2 on: January 09, 2024, 04:42:14 AM »
I dont understand, Is the alkyne a protecting group? What is it protecting?

Offline rolnor

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Re: Sonogashira Coupling hydroxy group removal Mechanism
« Reply #3 on: January 09, 2024, 04:53:21 AM »

As the first step, you just pick the proton from the hydroxyl group, forming a alkoholate and hydrogen gas.

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