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Author: Subject: aromatic Organic chemistry problem/ diels alder
alexleyenda
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[*] posted on 21-10-2015 at 01:40
aromatic Organic chemistry problem/ diels alder


Hi,
I had the following exercise to do (the b), I did it logically considering the reagents and formula given, but I have no god damn Idea how the hell one equivalent of buli would remove both Br and allow the reagent to make a diels-Alder reaction with the reagent in 2). Is anyone able to explain that / can tell me that i'm wrong and what should happen?



[Edited on 21-10-2015 by alexleyenda]

12167660_630939753715434_184301945_n.jpg - 42kB




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Metacelsus
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[*] posted on 21-10-2015 at 05:06


It looks to be forming a reactive benzyne intermediate.



As below, so above.
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CuReUS
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[*] posted on 22-10-2015 at 00:57


Quote: Originally posted by alexleyenda  
but I have no god damn Idea how the hell one equivalent of buli would remove both Br and allow the reagent to make a diels-Alder reaction with the reagent in 2). Is anyone able to explain that / can tell me that i'm wrong and what should happen?

It is possible,but I don't know how;)
http://www.orgsyn.org/demo.aspx?prep=v75p0201
https://en.wikipedia.org/wiki/Aryne#.5B4.2B2.5D_cycloadditio...
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UC235
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[*] posted on 22-10-2015 at 09:35


One equivalent of BuLi will lithiate the arene and generate BuBr as byproduct. Then eliminate LiBr to form the benzyne which is trapped by the diene.
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alexleyenda
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[*] posted on 22-10-2015 at 10:11


Oh I see, that is really an unusual reaction, thank you UC !



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