April 25, 2024, 09:47:33 AM
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Topic: Heck on an electron-rich aryl iodide  (Read 3110 times)

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Offline rucik5

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Heck on an electron-rich aryl iodide
« on: May 17, 2011, 06:01:04 PM »
Hi,
I've been recently trying to couple an electron-rich, o-substituted iodobenzene derivative with styrene.

The reaction worked very well with Pd(OAc)2, NEt3, PPh3 a 100°C on an electron-poor system [o-ester] but it doesn't want to go with the former. I was wondering whether anyone could recommend a different catalyst for that system? Pd(dppf)Cl2?
I reckon I might do a suzuki instead.
All advice and comments are welcome, thanks!

Offline g-bones

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Re: Heck on an electron-rich aryl iodide
« Reply #1 on: May 17, 2011, 08:35:55 PM »
you may need to use a more powerful phospine ligand to force oxidative addition.  try something like Cy3P or nBu3P.  There must be examples of these in the literature, have you given it a thorough search?  dppf doesnt seem unreasonable, it does have a large bite angle so it will help create some free coordination site on your metal center as well as encourage reductive elimination, but i dont think those are the issues you are facing, its more likely oxidative addition.  let us know how it goes!

Offline nox

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Re: Heck on an electron-rich aryl iodide
« Reply #2 on: May 18, 2011, 12:53:10 PM »
Try P(tBu)3, either the free ligand or the salt would work.

Offline rucik5

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Re: Heck on an electron-rich aryl iodide
« Reply #3 on: May 18, 2011, 06:47:46 PM »
Hi,
Thanks for the replies. I'll do some more lit and try the phosphines - you're probably right that it can't insert itself. Will update you soon!

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