October 09, 2024, 08:49:34 AM
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Topic: Isolation of Boronic Acid  (Read 1215 times)

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Offline yetyet

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Isolation of Boronic Acid
« on: September 10, 2024, 05:19:53 AM »
Hi, I am an undergraduate student conducting research on Suzuki-Miyaura polymerization.

After synthesizing the monomer by in-situ trapping, which is OHex, B(OH)2 and Br to the benzene ring. I have trouble in isolating the product as I can't fully extract the product using organic solvent from the mixture as I can always detect somthing (assuming the product since it is a boronic acid) on TLC plate. I tried Et2O and AcOEt but I still have the same problem.

If anyone have any idea how with this, it would help me a lot. Thank you!

Offline rolnor

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Re: Isolation of Boronic Acid
« Reply #1 on: September 18, 2024, 05:20:31 AM »

I dont understand what compound you are making. It sounds like an interesting project. Do you have a reference you are using, a paper? To isolate boronic acids can probably be a bit tricky, boron is different and can behave strangely.

Offline yetyet

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Re: Isolation of Boronic Acid
« Reply #2 on: September 21, 2024, 06:01:59 PM »
Thank you for replying rolnor.

The reference that i was using is https://doi.org/10.1021/ol015598+

The functional group here is OHex and with Bromine at the para-position. However, instead of working up with neopentyl glycol, I used HCl to convert it to Boronic Acid.

This reaction should worked because after reaction with neopentyl glycol I got a very good yield. So my only problem is isolating the Aryl Boronic Acid that i just synthesized.

Offline rolnor

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Re: Isolation of Boronic Acid
« Reply #3 on: September 22, 2024, 05:10:01 AM »
To mix this with HCl can give you a mess, why dont you use the boronic-ester? Try to follow the procedure you have is my tip. The OHex is a weak activating group and lithiation might be slow at -78, I have used OMe and in that case I used 0 degrees Celsius and BuLi for ortho-lithiation

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