[seb_ottawa]

A student over at my workplace had a question for me about the reaction mechanism that yields 4-methylcyclohexenone from the acid intrareaction of 3-methylacetylcyclobutene... here's the scheme (attached).

If anyone can help, it would be nice. This is in no way urgent, just pure organic chemistry fun, but I know I won't be able to rest until I find an answer, so please give it a shot too.

I have organic chemistry background - I graduated from my undergrad 3 years ago - but haven't really been working in the field since.  I keep looking in my textbooks and on the web, and can't seem to find a satisfying answer...

Thank you!

[movies]

It's a retro-aldol condensation followed by an aldol condensation from the other side of the ketone carbonyl.

[Dan]

Like this?

[seb_ottawa]

Thank you so much guys!  I forgot that H⁺ actually comes from H₃O⁺... hence providing much needed water molecule for reaction!  Small detail, but when you overlook it, question seemed nearly impossible to answer.

Mea culpa.