Chapter 11, Problem 11.58P

Interpretation Introduction

Interpretation:

A reasonable mechanism that accounts for the given reaction is to be proposed.

Concept introduction:

An electrophile is an electron deficient species that is attacked by a nucleophile, which is an electron-rich species. Alkenes can undergo acid-catalyzed hydration reactions in which the alkenes are treated with water in the presence of strong acids. The major product for these reactions is an alcohol.

Water (${\text{H}}^{\text{+}}{\text{and HO}}^{\text{-}}$) adds across the double bonded carbon atoms according to the Markovnikov’s rule. The addition of water to an alkene favors the product in which the proton adds to the alkene carbon that is initially bonded to a greater number of hydrogen atoms (to the least substituted carbon atom), thus forming a stable carbocation intermediate. The rearrangement of the carbocation intermediate may be possible. Finally, a proton transfer reaction must take place to form an uncharged product.

For the double bond present outside of the ring, the methyl carbons in the ring migrate, which converts the more strained ring to a less strained ring. These reactions are called ring expansion reactions, which involve migration of carbon.