Sciencemadness Discussion Board

aromatic Organic chemistry problem/ diels alder

alexleyenda - 21-10-2015 at 01:40

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

Metacelsus - 21-10-2015 at 05:06

It looks to be forming a reactive benzyne intermediate.

CuReUS - 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...

UC235 - 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.

alexleyenda - 22-10-2015 at 10:11

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