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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Traumatic Acid on September 14, 2020, 02:31:51 AM

Title: Diels-Alder pericyclic reaction mechanism proof check
Post by: Traumatic Acid on September 14, 2020, 02:31:51 AM

G'day ladies and germs.
I've been trying to figure out the mechanism behind the reaction between 2,3,4,5-Tetraphenylcyclopentadienone and dimethylacetylenedicarboxylate to form dimethyl-3,4,5,6-tetraphenylphthalate catalysed by dimethylformamide. That hurts to read so I will attach a photo of the general reaction.

My question is whether my working out of the mechanism (attached) is correct?
Steps 1 and 2 sure would not occur under normal conditions, so if someone could explain to me a bit about dimethylformamide that would be much appreciated.

Thanks :)

Title: Re: Diels-Alder pericyclic reaction mechanism proof check
Post by: AWK on September 14, 2020, 02:48:17 AM

Why are you opening the cyclopentadienone ring? The Diels-Alder reaction is followed by thermal decarbonylation.

Title: Re: Diels-Alder pericyclic reaction mechanism proof check
Post by: Traumatic Acid on September 14, 2020, 09:40:31 PM

More like this?

Title: Re: Diels-Alder pericyclic reaction mechanism proof check
Post by: AWK on September 15, 2020, 02:57:54 AM

OK

Title: Re: Diels-Alder pericyclic reaction mechanism proof check
Post by: wildfyr on September 16, 2020, 08:18:08 AM

Your first step arrows do not lead to the product shown in the second step. You never show the C-C bond breaking.