OChem 2 Final

Because the transition state requires the molecule to change from sp2 to sp and then back to sp2. The change from sp2 to sp requires far too much energy and the reaction would take much too long. (consider aromatic ring structures when thinking about this reaction, the ring can't change shape from sp2 to sp)

1) AlCl3 forms a complex with the acyl chloride OR pulls off the Chloride. Either method creates an area of positive charge over the carbonyl carbon (if it completely pulls off the Cl, the oxygen is triple-bonded to the carbon)

2) One of the aromatic double-bonds attacks the carbocation which creates a secondary carbocation on an adjacent position.

3) AlCl4- has a negative charge on the Al, so Cl leaves to pull a Hydrogen off of the aromatic ring which restores aromaticity.

It's a protecting group. You make it using a carbonyl compound and a glycol (can only create 5 or 6 membered rings)