January 24, 2022, 05:41:31 AM
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Topic: Lewis acid catalyzed reactions- how to get rid of the lewis acid afterwards?  (Read 6213 times)

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Offline chimiste

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Hello,

I have been doing Diels-Alders cycloadditions with various Lewis Acids, but I don't have a real idea about how to treat the reaction mixture after the reaction to isolate the cycloadduct. Is column chromatography enough to get rid of the Lewis acid or do it stay attached to the oxygen even after?

Offline azmanam

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You'll have to be more specific.  What dienes?  What dienophiles?  More importantly, what lewis acids?  Probably an aqueous extraction will be sufficient, depending on the lewis acids and functional group tolerance of the dienes/dienophiles/cyclohexenes.
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Offline chimiste

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You'll have to be more specific.  What dienes?  What dienophiles?  More importantly, what lewis acids?  Probably an aqueous extraction will be sufficient, depending on the lewis acids and functional group tolerance of the dienes/dienophiles/cyclohexenes.
I cannot give too many details, but as long as my product bears water I think I can do extraction, I've also seen research papers where they used extraction and then column chromatography, but I was wondering if I didn't do extraction they would stay connected after flash column chromatography. And as well one of my adducts is anhydride.
And why is the type of lewis acid important here?

Offline azmanam

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The type of L.A. matters if you're planning aqueous extraction.  some L.A's might not be compatible with water, etc.

It seems unlikely to me that the L.A. would stay coordinated after a column, but I cannot say for sure.

Extraction/chromatography is probably the way to go without knowing more details.
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Offline chimiste

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The type of L.A. matters if you're planning aqueous extraction.  some L.A's might not be compatible with water, etc.

It seems unlikely to me that the L.A. would stay coordinated after a column, but I cannot say for sure.

Extraction/chromatography is probably the way to go without knowing more details.

Thank you for your help, I just switched to a lewis acid which is compatible with water. So, I think I can do extraction. And in some papers, I see them doing just column, in some papers extraction+column, maybe just column is enough as well.

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