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Topic: Mechanism for removal of tboc group by tfa  (Read 23695 times)

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Offline mrsandman

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Mechanism for removal of tboc group by tfa
« on: February 25, 2009, 07:57:24 PM »
I have a question about deprotecting tboc group with tfa



I'm thinking that the Nitrogen will attack the carbonyl on TFA and form a tetrahedral intermediate.  Then the OH on TFA would be in proximity to the the carbonyl to the amide and that would attack and you would have like a cyclobutane like structure and the lone pairs would come down and in the end you woud have the tboc group attached to the tfa + the deprotected molecule.
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Offline mrsandman

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Re: Mechanism for removal of tboc group by tfa
« Reply #1 on: February 25, 2009, 11:49:14 PM »
nvm got it
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Offline expert

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Re: Mechanism for removal of tboc group by tfa
« Reply #2 on: February 26, 2009, 12:26:41 AM »
I don't know what you've found. Please share with us. I'm sure TFA protonates carbonyl group in CO(OBu-t) and the positive charge moves to t_Bu group that among alkyls stabilizes the positive charge the best. t_Bu+ cleaved from the molecule and gets quenched by any nucleophile available around, even if it'd CF3COO-. Obviously, CO2 released at the next stage.
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Offline Dynamic

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Re: Mechanism for removal of tboc group by tfa
« Reply #3 on: February 26, 2009, 08:43:40 PM »
Did you get isobutene as one of your products?
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Offline expert

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Re: Mechanism for removal of tboc group by tfa
« Reply #4 on: February 27, 2009, 01:08:06 AM »
You do, by loosing proton from Me3C+, if no good nucleophiles around.
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Offline ruler9

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Re: Mechanism for removal of tboc group by tfa
« Reply #5 on: November 06, 2009, 08:56:08 PM »
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Offline movies

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Re: Mechanism for removal of tboc group by tfa
« Reply #6 on: November 07, 2009, 02:19:17 PM »
Is the nitrogen of an amide the most basic part?  How would that change the mechanism you drew?
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