Electron-pushing mechanisms

Writing up my answer, almost done!

Any updates? :,)

I thought I had it, give me some more time sorry

No worries! I appreciate the effort!

i'm going to ask my colleague about this one, hang tight till tomorrow?

Sounds good, thank you!

Step 1:

If we count number of carbon in both reactant and product, there is same number of carbon present, somehow they undergo cyclization

For cyclization, 1st thing comes to our mind is the pericyclic reaction

Step 2:

Here in the reactant structure we can see there is one conjugated diene and one alkene present. in case of 4+2 cycloaddition, one diene and one dienophile are required, which is present in that molecule.

Simple orientation according to product converted by single bond rotation.

Step 3:



Step 4:

We know pericyclic 4+2 cycloaddition goes through the concerted mechanism. In the case of two-electron transfer 2 electrons of diene attack to the dienophile double bond which is conjugated with the carbonyl. And then dienophile donates two electrons to the other double bond of diene and they form cyclic six-member ring whole thing occurs in the concerted pathway

in the case of single electron transfer pathway it goes via homolytic cleavage, and radical pathways. Though it is concerted mechanism for easy to understand 1st I create radicals then couple them to form six-member ring.

My attempt