December 01, 2020, 10:33:00 PM
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Topic: Allyl oxidation  (Read 223 times)

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Offline Humr

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Allyl oxidation
« on: November 16, 2020, 04:05:42 AM »
Hello. I would like to ask if someone has idea what to use instead of tert-Butyl hydroperoxide in this reaction. I work with betuline and i cannot use peroxides because epoxide between C20 and C29 would form.

Offline rolnor

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Re: Allyl oxidation
« Reply #1 on: November 16, 2020, 07:29:12 AM »
What reaction do you want to do with betuline?

Offline Humr

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Re: Allyl oxidation
« Reply #2 on: November 16, 2020, 02:25:20 PM »
I want to have COOH on C30. I do this reaction only with SeO2 in glym. It does alhehyde on C30. I would be glad if i could skip second oxidation.

Offline rolnor

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Re: Allyl oxidation
« Reply #3 on: November 16, 2020, 06:00:34 PM »
Have checked Scifinder or Reaxys? It seems this should be possible to solve.
Here is a link, they use t-BuOOH but dont get epoxidation?
One more thing; If you do get epoxide you can convert it back to alkene with PPh3.
« Last Edit: November 16, 2020, 06:42:46 PM by rolnor »

Offline Humr

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Re: Allyl oxidation
« Reply #4 on: November 17, 2020, 08:55:51 AM »
Betuline is what i want to use. Reaction below is what i found in some literature. That is interesting idea.  So are you suggesting to use SeO2, T-BuOOH and PPh3 at once?

I have some idea too. How i normally do this reaction is: Disolve betuline in 2-metoxyethanol, add 2 eq. SeO2 and reflux for 4h.

What if i add Fehling's solution to this reaction?

Offline rolnor

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Re: Allyl oxidation
« Reply #5 on: November 17, 2020, 10:20:09 AM »
No, if you get epoxide you isolate this and treat with PPh3.
I think its better to include oxidation of the aldehyde as avseparate step, there are manyways to do this and yields should be high.

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