Chapter 11, Problem 11.59P

Interpretation Introduction

Interpretation:

The structures of compounds A through D in the given reaction scheme are to be determined.

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.

Sodium hydride is a strong base, which can deprotonate the hydrogen atom in the hydroxyl group in alcohols. This generates the nucleophile ${\text{O}}^{\text{-}}$. This nucleophile, when treated with an unsymmetrically substituted epoxide, attacks the least substituted (least sterically hindered) carbon on the epoxide.

Alcohols can be converted to alkyl bromides or alkyl chlorides when treated with phosphorous bromide or phosphorous chloride.

Alkyl halides undergo E2 elimination reaction in the presence of a strong base and heat. The most substituted alkene is the product for the E2 reaction.