$\mathrm{}\mathrm{}\mathrm{}\mathrm{}$ 

7.54 In Problem 7.20 (Section 7.13) we saw that acid-catalyzed dehydration of 2,2-dimethylcyclohexanol afforded 1,2- dimethylcyclohexene. To explain this product we must write a mechanism for the reaction in which a methyl shift transforms a secondary carbocation to a tertiary one. Another product of the dehydration of 2,2-dimethylcyclohexanol is isopropylidenecyclopentane. Write a mechanism to rationalize its formation, using curved arrows to show the flow of electrons. OH 2,2-Dimethylcyclohexanol H+ heat 1,2-Dimethylcyclohexene Isopropylidenecyclopentane