January 11, 2025, 01:11:23 AM
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Topic: Mechanism  (Read 2697 times)

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Offline H2lickwid

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Mechanism
« on: December 11, 2014, 01:21:10 PM »
I am trying to propose a plausible mechanisms for the reaction at the top of the page. I initially thought that a substitution is the only way to make the seven membered ring but realized that a sunstitution on the benzene is very unlikely. Is there a way that a Michael addition is a plausible way for this mechanisms to proceed? What are your ideas?

Offline orgopete

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Re: Mechanism
« Reply #1 on: December 11, 2014, 07:09:41 PM »
Hint, first step conjugate addition?
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Offline phth

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Re: Mechanism
« Reply #2 on: December 11, 2014, 07:55:55 PM »
The red arrows: what aromatic substitution mechanism do you think it undergoes?  Hint: its not SN2

Offline orgopete

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Re: Mechanism
« Reply #3 on: December 11, 2014, 11:41:35 PM »
The red arrows: what aromatic substitution mechanism do you think it undergoes?  Hint: its not SN2

Are you proposing the Ar-O bond becomes broken? I don't think it does.
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Offline phth

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Re: Mechanism
« Reply #4 on: December 12, 2014, 12:01:28 AM »
Pete: I mean E1cB

Offline H2lickwid

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Re: Mechanism
« Reply #5 on: December 12, 2014, 12:29:26 AM »
Thank you for your replies. I initially thought this proceeded via an sn2 mechanism but realize that it is very unlikely. The ec1b seems much more likely, thank you!!!

Offline orgopete

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Re: Mechanism
« Reply #6 on: December 13, 2014, 07:04:27 AM »
I don't agree with the curved arrow mechanism. I think it is a conjugate addition, deprotonation of the hemiacetal to form the aldehyde and phenoxide, and then an alkylation of the phenoxide with the bromide.
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

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