Aldehydes, Ketones & Carboxylic Acids - Reaction Involving C-H Bond, Ewg Eg, Hvz Reaction

Aldehydes, Ketones & Carboxylic Acids

Reaction involving C-H bond
Electronegative groups (EWG)
Haloform reaction (HVZ reaction)
Examples of reactions
Common reagents and conditions

Reaction involving C-H bond

Aldehydes and ketones can undergo reactions that involve the cleavage of a C-H bond
These reactions are important for the synthesis of complex organic compounds
Common reactions include oxidation, reduction, and substitution

Electronegative groups (EWG)

Electronegative groups, such as nitro (NO2) and cyano (CN), increase the reactivity of aldehydes and ketones
They activate the C-H bond towards nucleophilic attack or oxidation reactions
This is due to the presence of electron-withdrawing substituents that enhance the polarity of the C-H bond

Haloform reaction (HVZ reaction)

The haloform reaction is a method to convert methyl ketones into haloforms (compounds containing a halogen atom)
The reaction proceeds in the presence of a strong base, such as sodium hydroxide (NaOH) or potassium hydroxide (KOH)
It involves the successive halogenation and hydrolysis of the methyl ketone

Examples of reactions

Oxidation of aldehydes to carboxylic acids using oxidizing agents like potassium permanganate (KMnO4)
Reduction of ketones to secondary alcohols using reducing agents like sodium borohydride (NaBH4)
Nucleophilic addition reactions with various nucleophiles, such as Grignard reagents and cyanide ions

Common reagents and conditions

Oxidation: Potassium permanganate (KMnO4) in acidic medium
Reduction: Sodium borohydride (NaBH4) in alcoholic solvent
Nucleophilic addition: Grignard reagents (RMgX) in ether solvent, or cyanide ions (CN-) in the presence of a base

Oxidation of Aldehydes

Aldehydes can be oxidized to carboxylic acids
This reaction involves the breaking of a C-H bond and the formation of a C-O bond
Common oxidizing agents include potassium permanganate (KMnO4) and chromic acid (H2CrO4)
Example: Oxidation of ethanol to acetic acid using potassium permanganate

Redox Reaction

Redox reactions involve the transfer of electrons between reactants
In oxidation, a species loses electrons and increases its oxidation state
In reduction, a species gains electrons and decreases its oxidation state
Example: Reduction of acetone to isopropanol using sodium borohydride

Nucleophilic Addition

Aldehydes and ketones can undergo nucleophilic addition reactions
Nucleophiles attack the electrophilic carbon of the carbonyl group
This results in the formation of a new bond to the carbon and breaking of the carbonyl bond
Example: Addition of Grignard reagent (RMgX) to a ketone to form an alcohol

Cyanohydrin Formation

Cyanohydrin formation is a type of nucleophilic addition reaction
It involves the addition of cyanide ion (CN-) to the carbonyl group
The reaction results in the formation of a cyanohydrin, which contains a hydroxyl group and a cyano group
Example: Formation of cyanohydrin from benzaldehyde and hydrogen cyanide (HCN)

Aldol Condensation

Aldol condensation is a type of nucleophilic addition reaction between two carbonyl compounds
It involves the formation of a carbon-carbon bond and the elimination of water
The reaction is catalyzed by a base, such as sodium hydroxide (NaOH)
Example: Condensation of acetone and benzaldehyde to form a β-hydroxy ketone

Cannizzaro Reaction

The Cannizzaro reaction is a disproportionation reaction of aldehydes
It involves the simultaneous oxidation and reduction of the same aldehyde molecule
The reaction is often carried out in the presence of a strong base, such as sodium hydroxide (NaOH)
Example: Cannizzaro reaction of benzaldehyde to form benzoic acid and benzyl alcohol

Acidity of Carboxylic Acids

Carboxylic acids are weak acids due to the presence of a carboxyl group (COOH)
They can donate a proton (H+) to a base
The acidity of carboxylic acids increases with the presence of electron-withdrawing groups on the molecule
Example: Acetic acid is a weak acid, while trichloroacetic acid is a stronger acid

Esterification

Esterification is the reaction between a carboxylic acid and an alcohol
It involves the formation of an ester and the elimination of water
The reaction is often catalyzed by an acid, such as concentrated sulfuric acid (H2SO4)
Example: Esterification of acetic acid and ethanol to form ethyl acetate

Hydrolysis of Esters

Hydrolysis of esters involves the cleavage of the ester bond by water
It can be acid-catalyzed or base-catalyzed
Acidic hydrolysis forms a carboxylic acid and an alcohol, while basic hydrolysis forms a carboxylate ion and an alcohol
Example: Acidic hydrolysis of ethyl acetate to form acetic acid and ethanol

Saponification

Saponification is the hydrolysis of esters in the presence of a base, such as sodium hydroxide (NaOH)
It results in the formation of a carboxylate ion and an alcohol
Saponification is commonly used in the production of soaps from fats and oils
Example: Saponification of triglycerides to form glycerol and soap

Electrophilic Addition to α,β-Unsaturated Carbonyl Compounds

α,β-Unsaturated carbonyl compounds have a double bond conjugated with a carbonyl group
They undergo electrophilic addition reactions with nucleophiles
The nucleophile attacks the electrophilic carbon of the carbonyl group, leading to the formation of a new bond
Example: Addition of HCl to methyl vinyl ketone to form a chlorohydrin

Baeyer-Villiger Oxidation

Baeyer-Villiger oxidation is a reaction that converts ketones into esters or lactones
It involves the insertion of an oxygen atom between the carbonyl group and a neighboring carbon
The reaction is often carried out using a peroxyacid, such as m-chloroperbenzoic acid (m-CPBA)
Example: Baeyer-Villiger oxidation of cyclohexanone to form ε-caprolactone

Claisen Condensation

Claisen condensation is a reaction between two ester molecules or an ester and a ketone/aldehyde
It involves the formation of a carbon-carbon bond and the elimination of an alcohol molecule
The reaction is often catalyzed by a base, such as sodium ethoxide (NaOEt)
Example: Claisen condensation between ethyl acetate and ethyl propanoate to form ethyl 3-oxobutanoate

Decarboxylation

Decarboxylation is the loss of a carbon dioxide molecule from a carboxylic acid or its derivative
It is commonly observed in the heating or refluxing of the compounds
The reaction leads to the formation of a lower molecular weight compound
Example: Decarboxylation of benzoic acid to form benzene

Fischer Esterification

Fischer esterification is the reaction between a carboxylic acid and an alcohol
It involves the formation of an ester and the elimination of water
The reaction is catalyzed by an acid, such as concentrated sulfuric acid (H2SO4)
Example: Fischer esterification of acetic acid and methanol to form methyl acetate

Gabriel Synthesis

Gabriel synthesis is a method to prepare primary amines from phthalimide derivatives
The reaction involves the nucleophilic substitution of a halogen atom in the phthalimide derivative
The resulting intermediate undergoes hydrolysis to give the primary amine
Example: Gabriel synthesis of 1-aminobutane from phthalimide

Hell-Volhard-Zelinsky (HVZ) Reaction

The Hell-Volhard-Zelinsky (HVZ) reaction is a method to convert carboxylic acids into α-halo acids
It involves the bromination of the α-carbon of the carboxylic acid
The reaction is carried out in the presence of phosphorus tribromide (PBr3)
Example: HVZ reaction of acetic acid to form α-bromoacetic acid

McMurry Reaction

The McMurry reaction is a method to synthesize symmetrical or unsymmetrical alkanes
It involves the coupling of two carbonyl compounds in the presence of a titanium-based reagent
The reaction results in the formation of a carbon-carbon double bond
Example: McMurry reaction of acetone and benzaldehyde to form dibenzyl

Oxidative Cleavage

Oxidative cleavage is a reaction that breaks a carbon-carbon double bond or a carbon-carbon triple bond
It involves the addition of an oxidizing agent, such as ozone or potassium permanganate (KMnO4)
The resulting products are aldehydes or ketones, depending on the reaction conditions
Example: Oxidative cleavage of cyclohexene to form adipic acid

Arene Diazonium Salts

Arene diazonium salts are compounds containing a diazonium group (-N≡N+) attached to an aromatic ring
They are versatile intermediates in organic synthesis, capable of undergoing various reactions
Examples of reactions include nucleophilic substitution, Sandmeyer reaction, and azo coupling
Example: Formation of p-nitrophenol from p-nitroaniline via diazotization and hydrolysis