19: Ketones and Aldehydes
- Page ID
- 424361
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After reading this chapter and completing ALL the exercises, a student can be able to
- describe the structure and physical properties of aldehydes and ketones (section 19.1)
- determine the structure of aldehydes and ketones from their elemental analysis and spectral data (MS, IR 1H NMR & 13C NMR) (section 19.2)
- predict the products and specify the reagents to synthesize aldehydes and ketones for reactions studied to date (section 19.3)
- predict the products and specify the reagents to synthesize aldehydes and ketones for new reactions (section 19.4)
- write the general mechanism for nucleophilic addition reactions with aldehydes and ketones (sections 19.5 to 19.11, 19.13, & 19.15)
- predict the relative reactivity of carbonyl compounds to nucleophilic addition reactions (sections 19.5 to 19.13, & 19.15)
- predict the relative equilibrium constant & rates of hydration for aldehydes and ketones (section 19.6)
- show the general mechanism for the Wittig reaction (section 19.13)
- predict the products and specify the reagents for oxidation and reduction reactions of aldehydes and ketones (section 19.14 and 19.15)
- combine the reactions studied to date to develop efficient and effective multiple-step synthesis including the use of acetals/ketals as protecting groups (sect 19.12)
Please note: IUPAC nomenclature and important common names of aldehydes and ketones were explained in Chapter 3.
- 19.1: Carbonyl Compound Structure and Properties
- While there are several functional groups that include a carbonyl structural feature, the term "carbonyls" is used to describe aldehydes and ketones.
- 19.2: Spectroscopy of Ketones and Aldehydes
- The carbonyl structural feature plays a prominent role in the spectroscopy of aldehydes and ketones.
- 19.3: Review of Ketone and Aldehyde Synthesis
- So far this text has discussed aldehyde and ketone synthesis from the ozolysis of alkenes, hydration of alkynes, oxidation of alcohols, and Friedel-Crafts acylation of benzene rings.
- 19.4: 19.4 New Synthesis of Aldehydes and Ketones
- Aldehydes and ketones can also be synthesized from esters, acid chlorides, carboxylic acids, and nitriles.
- 19.5: Nucleophilic Addition Reactions of Ketones and Aldehydes
- Since aldehydes and ketones are good electrophiles, they undergo nucleophilic addition reactions with a wide range of nucleophiles.
- 19.6: Nucleophilic Addition of Water (Hydration)
- Hydration of aldehydes and ketones (carbonyls) preduces gem-diols. This reaction demonstrates a correlation between steric hindrance and relative equilibrium of hydrate formation.
- 19.7: Nucleophilic Addition of Cyanide and Acetylide
- Cyanide and acetylide ions are strong nucleophiles with partial negative charge on the carbon. These reactions increase carbon chain length and can be useful for multiple step synthesis.
- 19.8: Nucleophilic Addition of Grignards
- Organometallic reagents are excellent nucleophiles and react with the electrophilic carbon in the carbonyl to form alcohols.
- 19.9: Nucelophilic Addition of Amines (Imine and Enamine Formation)
- The reaction of aldehydes and ketones with ammonia or 1º-amines forms imine derivatives, also known as Schiff bases (compounds having a C=N function). Most aldehydes and ketones react with 2º-amines to give products known as enamines.
- 19.10: Nucleophilic Addition of Hydrazine (Wolff-Kishner Reaction)
- Aldehydes and ketones can be reduced to alkanes using the Wolff-Kishner reaction sequence.
- 19.11: Nucelophilic Addition of Alcohols (Acetal Formation)
- Alcohols add reversibly to aldehydes and ketones to form hemiacetals. This reaction can continue by adding another alcohol to form an acetal. Hemiacetals and acetals are important functional groups because they appear in sugars.
- 19.12: Acetals as Protecting Groups
- For compounds with multiple functional groups, it may be necessary to protect one group while reacting the other one.
- 19.13: Nucelophilic Addition of Phosphorus Ylides (The Wittig Reaction)
- Organophosphorus ylides react with aldehydes or ketones to give substituted alkenes in a transformation called the Wittig reaction.
- 19.14: Oxidation of Aldehydes
- Aldehydes are so easily oxidized that oxidation reactions can be an unwanted side reaction. Isolated ketones cannot be oxidized.
- 19.15: Reductions of Ketones and Aldehydes
- Hydride reductions are another example of a nucleophilic addition reaction of carbonyls. Carbonyl reductions were introduced during the alcohol synthesis chapter.
- 19.16: Additional Exercises
- This section has additional exercises for the key learning objectives of the chapter.
- 19.17: Solutions to Additional Exercises
- This section has the solutions to the additional exercises from the previous section.