[allydom]

Could someone help me with this mechanism?  I know it is an acid catalyzed rearrangement, and forms carbocation intermediates, but I'm not exactly sure what happens..

TIA

[majorjp]

It's a pinacol-pinacolone rearrangement, therefore a carbocation is formed by the protonation of on of the hydroxyl groups. This forms a the carbocation, which is then stabilized via the migration of one of the phenols from the adjacent carbon to the carbocation carbon. In this structure the carbocation become the carbon with the hydroxyl group which leads to the deprotanation of the O of the hydroxyl group to form a double bond between the O and the C.