Addition Reactions of Alkenes

Alkenes are unsaturated hydrocarbons that contain at least one carbon-carbon double bond. Due to the presence of a double bond, alkenes undergo addition reactions. Addition reactions involve the addition of atoms or groups of atoms to the carbon-carbon double bond, resulting in the formation of a single bond.

Examples of addition reactions of alkenes include:

1. Hydrogenation: In the presence of a catalyst such as platinum or palladium, alkenes can be converted to alkanes by the addition of hydrogen. This reaction is known as hydrogenation.

2. Halogenation: Alkenes react with halogens such as chlorine or bromine to form dihaloalkanes. This reaction is known as halogenation.

3. Hydrohalogenation: Alkenes react with hydrogen halides such as HCl or HBr to form alkyl halides. This reaction is known as hydrohalogenation.

4. Hydration: Alkenes react with water in the presence of an acid catalyst such as sulfuric acid to form alcohols. This reaction is known as hydration.

5. Oxymercuration-Demercuration: This reaction involves the addition of a mercuric acetate compound to the alkene, followed by the addition of sodium borohydride. This reaction is known as oxymercuration-demercuration.

6. Hydroboration-Oxidation: This reaction involves the addition of borane to the alkene, followed by the addition of hydrogen peroxide and sodium hydroxide. This reaction is known as hydroboration-oxidation.

Addition Reaction not undergone by Alkenes

The addition reaction that is not undergone by alkenes is mercuration. Mercuration involves the addition of a mercuric acetate compound to a substrate, and alkenes are not substrates for this reaction. Instead, mercuration is commonly used to add a carbonyl group to an aromatic ring, or to add a hydroxyl group to an alkene or alkyne in the presence of a nucleophile.