Aldehydes and Ketones— Nucleophilic Addition Chapter 21 Aldehydes and Ketones— Nucleophilic Addition

1. Introduction

2. Nomenclature of Aldehydes

3. Nomenclature of Ketones common names

Two examples of ketone nomenclature most common acyl groups:

3. Physical Properties

4. Interesting Aldehydes and Ketones

5. Preparation of Aldehydes and Ketones Common methods to synthesize aldehydes:

Common methods to synthesize ketones:

Preparation of Aldehydes and Ketones

6. Reactions of Aldehydes and Ketones—General [1] Reaction at the carbonyl carbon. [2] Reaction at the  carbon.

Cl¯, Br¯ and I¯ are good nucleophiles in substitution reactions at sp3 hybridized carbons, but they are ineffective nucleophiles in addition.

7. Nucleophilic Addition of H¯ and R¯ Hydride reduction occurs via a two-step mechanism.

Nucleophilic addition occurs via a two-step mechanism.

8. Nucleophilic Addition of ¯CN

Cyanohydrins can be reconverted to carbonyl compounds by treatment with base. The cyano group of a cyanohydrin is readily hydrolyzed to a carboxy group by heating with aqueous acid or base.

8. The Wittig Reaction

Wittig reagents are synthesized by a two-step procedure.

Mechanism of the Wittig reaction.

Limitation of the Wittig reaction

Advantage of the Wittig reaction

9. Addition of 10 Amines—Formation of Imines

In imine formation, mild acid is needed

The key reaction in the chemistry of vision

10. Addition of 2° Amines—Formation of Enamines

Imine and Enamine Hydrolysis

11. Addition of H2O—Hydration

11. Addition of Alcohols—Acetal Formation

12. Acetals as Protecting Groups

[1] Protect the interfering functional group—the ketone carbonyl. [2] Carry out the desired reaction. [3] Remove the protecting group.

Cyclic Hemiacetals

13. Introduction to Carbohydrates