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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: phenooo on October 08, 2013, 03:23:51 PM

Title: Help appreciated! Scoured many resources, couldn't solve this problem.
Post by: phenooo on October 08, 2013, 03:23:51 PM

Hi Guys,
I'm not too great at Ochem, but I do study hard and just had a question about this reaction. My understanding is that AlCl3 will pull off the Cl and form a sort of acylium ion. But I don't know if I'm doing this right because I can't get it to form anything with 6 proton environments. My thought is that the double bond in the benzene near the substituent would form a bond to the cation on the 4th carbon of the substituent with the ketone attached. Is my thought process correct? Any help much much appreciated. Thank you!

Title: Re: Help appreciated! Scoured many resources, couldn't solve this problem.
Post by: phenooo on October 08, 2013, 03:32:24 PM

So this is what I came up with, but I'm positive this is wrong and doesn't even look right and it doesn't have the 6H+ environments.

Title: Re: Help appreciated! Scoured many resources, couldn't solve this problem.
Post by: Dan on October 08, 2013, 04:00:22 PM

Well, you should trust your instincts. It is indeed an intramolecular Friedel-Crafts acylation (http://www.organic-chemistry.org/namedreactions/friedel-crafts-acylation.shtm).

Note that in your NMR, the peak at 7.3-7.2 ppm is two overlapping signals.

Title: Re: Help appreciated! Scoured many resources, couldn't solve this problem.
Post by: Altered State on October 08, 2013, 04:00:49 PM

Review (intramolecular) Friedel craft's acylation mechanism, you need to regenerate aromaticity.

Edit: Wops, Dan was 27 seconds faster  :)

Title: Re: Help appreciated! Scoured many resources, couldn't solve this problem.
Post by: Dan on October 08, 2013, 04:04:36 PM

Quote from: Altered State on October 08, 2013, 04:00:49 PM

you need to regenerate aromaticity.

I missed that though, good spot.

Title: Re: Help appreciated! Scoured many resources, couldn't solve this problem.
Post by: phenooo on October 08, 2013, 04:19:35 PM

Thanks so much guys. Helped a lot. My teacher doesn't teach from the book and never mentioned this reaction before or the name so I was a little confused. It was on a handout.