[Traumatic Acid]

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

[AWK]

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

[Traumatic Acid]

More like this?

[AWK]

OK

[wildfyr]

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