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Named Reactions are chemical reactions that are named after the people who discovered the reaction mechanisms. This trend of naming organic reactions began in the 20th century when the reaction was named after their respective developers. The naming of reactions facilitates easier interpretation of the transformation occurring in reactions rather than going into detail.
These reaction mechanisms are used for various applications such as converting alcohol into functional groups such as esters in the Mitsunobu Reaction. Some of the most commonly named reactions include Gattermann- reaction, Friedel-Crafts Acylation, etc.
Read More: NCERT Solutions Class 12 Chemistry
Key Terms: Named Reactions, Reaction Mechanisms, Organic Chemistry, Product, Reactant, Organic Compound
What are Named Reactions?
The named reactions is a set of chemical reactions that are named after their discoverer. Named reactions in chemistry follow a certain mechanism to yield the end product. Some of the important named reactions in organic chemistry are covered in this article along with the equations explaining the reaction mechanism.
1. What is Aldol Condensation?
Aldol Condensation is an organic reaction mechanism where a carbonyl compound reacts with an enolate ion to form a β-hydroxy aldehyde or a β-hydroxy ketone, which is then followed by dehydration, to give a conjugated enone.
Aldol Condensation Mechanism
Questions on Aldol Condensation
Ques. What are the applications of Aldol Condensation?
Ans. The reaction is used:
- For the production of solvents such as diacetone and isophorone.
- To produce plasticizers
- As an intermediate in order to manufacture perfume.
Ques. Which product is formed during Aldol Condensation?
Ans. The aldol condensation process takes place between 2 molecules of ketone or aldehyde with at least one hydrogen atom. This happens in the presence of a catalyst and forms a β-hydroxy aldehyde or ketone.
2. What is Wurtz Reaction?
Wurtz Reaction is a coupling reaction mechanism in organic chemistry that takes place between two alkyl halides and sodium metal. It takes place in the presence of a dry ether solution to form a higher alkane. The name reaction is named after its discoverer, the French chemist Charles Adolphe Wurtz.
Wurtz Reaction Mechanism
Questions on Wurtz Reaction
Ques. What happens when methyl chloride is treated with Na in presence of dry ether? (NCERT Question)
Ans. When methyl chloride reacts with Na in the presence of dry ether, ethane is formed through the Wurtz reaction.
Ques. Write the Wurtz reaction between bromo-ethene and 1-bromobutane. How many products will be formed?
Ans. If different alkyl halides are used to prepare an alkane with an odd number of carbon atoms, a variety of products are formed instead of a single alkane. This is because three reactions take place in this case and three products are obtained.
For instance, bromoethane and 1-bromobutane result in a mixture of octane, butane, and hexane
3. What is Wurtz Fittig Reaction?
Wurtz-Fittig Reaction is an organic name reaction mechanism in which one aryl halide and one alkyl halide react along with sodium metal in the presence of dry ether to form aromatic compounds. The reaction mechanism is named after Wilhelm Rudolph Fittig who discovered it by extending the work of Charles Wurtz.
Wurtz-Fittig Reaction Mechanism
Questions on Wurtz Fittig Reaction
Ques. Give an example of Wurtz Fittig reaction?
Ans. Wurtz Fittig Reaction mechanism involves the reaction of an aryl halide and alkyl halide to form the corresponding hydrocarbon. For example:
Ques. What are the 2 reaction mechanisms of Wurtz Fittig reaction?
Ans. The reaction mechanisms of Wurtz Fittig reaction are:
- Organo Alkali Mechanism: When aryl halide reacts with sodium metal, the formation of an intermediate organo-alkali compound takes place. This is then followed by a nucleophilic attack of the alkyl halide. Therefore, the required alkyl-aryl is formed.
- Radical Mechanism: The sodium atom acts as a kind of moderator to form alkyl radicals and aryl radicals, which combine together to form a substituted aromatic compound.
4. What is Cannizzaro Reaction?
Cannizzaro Reaction is a reaction mechanism that requires a base-induced disproportionation of 2 molecules that belong to a non-enolizable aldehyde to produce a carboxyl group and primary alcohol.
Cannizzaro Reaction Mechanism
The reaction is named after the Italian Chemist Stanislao Cannizzaro who discovered it in 1853. It is similar to the Aldol Condensation Reaction in a lot of ways. A major difference between both name reactions is that the Cannizaro reaction is carried out by those aldehydes which do not contain a hydrogen atom.
Questions on Cannizzaro Reaction
Ques. What type of aldehydes undergo Cannizaro reaction? (Comptt. Delhi 2017)
Ans. Aldehydes which do not contain α-hydrogen atoms undergo a Cannizzaro reaction e.g. Formaldehyde (HCHO) and Benzaldehyde (C6H5CHO).
Ques. What are the requirements of Cannizzaro Reaction?
Ans. The following requirements are needed in order to carry out a Cannizzaro reaction:
- Aromatic aldehydes that do not contain an α-hydrogen, for instance, benzaldehyde or C6H5CHO
- Aliphatic aldehydes that do not contain an α-hydrogen, for instance, HCHO or (CH3)3CCHO
- Concentrated aqueous alkali (NaOH or KOH)
Ques. What are the products formed in Cannizzaro's reaction?
Ans. The reactants of the reaction undergo reduction and self-oxidation to form alcohol and the salt of the corresponding carboxylic acid.
5. What is Clemmensen Reduction?
Clemmensen Reduction mechanism involves a reaction in which a ketone is reduced to alkenes. The organic chemistry name reaction is carried out with the help of zinc amalgam and concentrated hydrochloric acid. It was discovered by a Danish Chemist named Erik Christian Clemmensen.
Clemmensen Reduction Mechanism
Questions on Clemmensen Reduction
Ques. Which catalyst is used in Clemmensen reduction?
Ans. Concentrated HCl and Zinc Amalgam are used as catalysts in Clemmensen reduction.
Ques. Why zinc amalgam is used in Clemmensen reduction?
Ans. The zinc amalgam is used in the Clemmensen Reduction as the reaction of zinc with HCl releases hydrogen gas (H2). Hence, zinc amalgam works to trap the active hydrogen gas as it is formed.
Ques. Write the reactions involved in the following reactions: (Delhi 2017)
(i) Clemmensen reduction
(ii) Cannizzaro reaction
Ans. (i) Clemmensen reduction- The carbonyl group of aldehyde and ketones is reduced to CH2 group on treatment with zinc amalgam and concentrated hydrochloric acid.
(ii) Cannizzaro reaction- Aldehydes, which do not have an a-hydrogen atom undergo self oxidation and reduction on treatment with cone, alkali and produce alcohol and carboxylic acid salt.
6. What is Carbylamine Reaction?
Carbylamine reaction mechanism involves the reaction of a basic amine, chloroform and a base for synthesizing isocyanides. Another name for the Carbylamine reaction is Hofmann isocyanide synthesis. Since the reaction deals only with primary amines, it is also used as a chemical test to detect the presence of primary amines
Carbylamine Reaction Mechanism
Questions on Carbylamine Reaction
Ques. What is the main product of carbylamine reaction?
Ans. Carbylamine reaction mechanisms are used to form isocyanides from the primary amines with the help of a base and chloroform.
Ques. Why secondary and tertiary amines do not give carbylamine test?
Ans. Secondary and tertiary amines fail to undergo the carbylamine test as they react with the alcoholic KOH.
7. What is Balz-Schiemann Reaction?
Balz-Schiemann Reaction is used to transform a primary aromatic amine into an aryl fluoride. The transformation mechanism is carried out via the diazonium tetrafluoroborate intermediate, after which the thermal decomposition of the derived tetrafluoroborates or hexafluorophosphate takes place. The reaction was discovered by Gunther Schiemann and Gunther Balz.
Balz-Schiemann Reaction Mechanism
Questions on Balz-Schiemann Reaction
Ques. What are the reactants of Balz-Schiemann reaction?
Ans. The basic reactants of the Balz Schiemann reaction are nitrous acid, aromatic amines, and fluoroboric acid.
Ques. What is the general reaction of Balz-Schiemann Reaction?
Ans. 
8. What is Etard Reaction?
Etard Reaction mechanism involves the oxidation of an aromatic or heterocyclic bound methyl group that converts it into an aldehyde, like the oxidation of toluene to benzaldehyde. The reaction is carried out using chromyl chloride. Etard Reaction is named after French Chemist Alexandre Leon Etard.
Etard Reaction Mechanism
Questions on Etard Reaction
Ques. What is the reagent used in the Etard reaction?
Ans. The reagent used in this reaction is chromyl chloride.
Ques. What is the use of CS2 in Etard reaction?
Ans. Carbon disulfide and chloroform are used as solvents in the Etard reaction. The alkene-allylic hydrogen of the aromatic ring reacts in turn with chromyl chloride, Etard reagent, and forms Etard complex precipitate.
Ques. Write the equations involved in the following reactions:
(i) Wolff-Kishner reduction
(ii) Etard reaction (Delhi 2017)
Ans. (i) Wolff-Kishner reduction
(ii) Etard reaction
9. What is Finkelstein Reaction?
Finkelstein Reaction mechanism involves the exchange of one halogen atom through Nucleophilic Substitution Bimolecular reaction. The reaction was given by German chemist Hans Finkelstein.
Finkelstein Reaction Mechanism
Questions on Finkelstein Reaction
Ques. Why acetone is used in Finkelstein reaction?
Ans. Acetone acts as an organic solvent in anhydrous conditions. This means that when acetone is pure, it is used in Finkelstein's reaction in order to facilitate the forward reaction as per Le Chatelier's Principle.
Ques. On what conditions does the success of Finkelstein's reaction depend?
Ans. The success of the reaction depends on the below conditions.
- Nature of group
- Nucleophilicity
- Alkyl Halide reactivity
- Carbon-halogen bond
10. What is Friedel Crafts Reaction?
Friedel Crafts Reaction mechanism specifies various ways of attaching substitutes to aromatic rings. Two of the major types include alkylation and acylation reactions. These reactions were developed by Charles Friedel and James Crafts in 1877.
- Friedel Crafts Alkylation mechanism involves the attachment of an alkyl group by the replacement of an aromatic proton through an electrophilic attack on the aromatic ring. This is done with the help of carbocation.
- Friedel-Crafts Acylation is a reaction in which an acyl group is added to the aromatic ring by using an acid chloride (R-(C=O)-Cl) and a Lewis acid catalyst.
Friedel Crafts Reaction Mechanism
Questions on Friedel Crafts Reaction
Ques. Name a compound that does not undergo Friedel-Craft reaction easily?
Ans. Nitrobenzene does not undergo Friedel Craft reaction. This is because the nitro group of the nitrobenzene is strongly electron-withdrawing in nature and therefore deactivates the ring.
Ques. Why cannot cations such as Na+ and K+ be used in the Friedel Crafts reaction?
Ans. Cations such as Na+ and K+ have little tendency to accept the electrons because of their inert gas configuration. Therefore, they can not be used in Friedel's Craft reaction.
Ques. (a) Describe the following giving chemical equations :
(i) De-carboxylation reaction (ii) Friedel-Crafts reaction
(b) How will you bring about the following conversions?
(i) Benzoic acid to Benzaldehyde (ii) Benzene to m-Nitroacetophenone (iii) Ethanol to 3-Hydroxybutanal (Comptt. Delhi 2015)
Ans. (i) De-carboxylation reaction: When sodium salt of a carboxylic acid is heated with soda lime (NaOH + CaO), the corresponding alkane and CO2 will be evolved
(ii) Friedel-Crafts reaction: The introduction of alkyl or acetyl group in the presence of anhydrous almuninium chloride (AlCl3) as a catalyst to ortho and para positions of an aromatic compound is called Friedel-Crafts reaction,
11. What is Gabriel Phthalimide Reaction?
Gabriel Phthalamide mechanism involves the transformation of primary alkyl halides into a primary amine. German chemist Siegmund Gabriel developed the reaction.
Questions on Gabriel Phthalimide Reaction
Ques. How primary amines are prepared by Gabriel phthalimide synthesis?
Ans. Gabriel phthalimide synthesis mechanism is used to prepare aliphatic primary amines through the SN2 nucleophilic substitution of alkyl halides through the anion formed by the phthalimide.
Ques. Which of the amines are not prepared by Gabriel synthesis?
Ans. Gabriel Synthesis cannot form aromatic amines. This is because aryl halides don’t undergo nucleophilic substitution with the salt that is formed by phthalimide
12. What is Gattermann Reaction?
Gattermann Reaction mechanism involves the formation of aromatic compounds in the presence of a mixture of hydrogen cyanide and hydrogen chloride along with a Lewis base catalyst. It is named after the German chemist Ludwig Gattermann.
Gattermann Reaction Mechanism
Question on Gattermann Reaction
Ques. What type of organic compounds are obtained by Gattermann reaction?
Ans. Gatterman reaction mechanism is used to form aromatic compounds. This reaction can help to form Aromatic aldehyde and aromatic halide.
Ques. What is the mechanism of Gattermann reaction?
Ans. 
13. What is Gattermann-Koch Reaction?
Gattermann-Koch Reaction is a named reaction that follows the same mechanism as the Gattermann Reaction but instead of hydrogen cyanide, carbon monoxide is used. Along with Ludwig Gattermann, it is named after another German chemist Julius Arnold Koch.
Gattermann-Koch Reaction Mechanism
Questions on Gattermann-Koch Reaction
Ques. What is the difference between Gattermann and Gattermann-Koch reactions?
Ans. The key difference between Gattermann and Gattermann Koch's reactions is that the Gattermann reaction uses a mixture of hydrochloric acid and hydrogen cyanide, whereas the Gattermann Koch's reaction uses carbon monoxide (CO) instead of hydrogen cyanide.
Ques. Which catalyst is used in Gattermann-Koch reaction?
Ans. In the Gattermann – Koch reaction, benzene is treated with carbon monoxide (CO) in an acidic medium. This is done in the presence of anhydrous aluminium chloride in order to yield benzaldehyde. Anhydrous aluminium chloride works as a catalyst in this reaction.
14. What is Hell-Volhard Zelinsky Reaction?
Hell-Volhard Zelinsky Reaction involves the halogenation of carboxylic acids at the alpha-carbon place. The reaction was discovered by two German scientists Carl Magnus von Hell, Jacob Volhard, and Russian scientist Nicolay Zelinsky.
Hell-Volhard Zelinsky Reaction Mechanism
Questions on Hell-Volhard Zelinsky Reaction
Ques. Why is the mechanism of the Hell-Volhard Zelinsky reaction different from other halogenation reactions?
Ans. The mechanism of Hell Volhard Zelinsky Reaction Mechanism is very different from other halogenation reactions. This is because it takes place in the absence of a halogen carrier.
Ques. Give an example of Hell Volhard Zelinsky's reaction.
Ans. 
Ques. (a) Illustrate the following name reactions giving suitable example in each case :
(i) Clemmensen reduction (ii) Hell-Volhard-Zelinsky reaction
(b) How are the following conversions carried out?
(i) Ethylcyanide to ethanoic acid (ii) Butan-l-ol to butanoic acid
(iii) Benzoic acid to m-bromobenzoic acid (Delhi 2012)
Ans. (i) Clemmensen reduction: The carbonyl group of aldehyde and ketones is reduced to CH2 group on treatment with zinc amalgam and concentrated hydrochloric acid.
(ii) Hell-Volhard-Zelinsky reaction: Carboxylic acid reacts with chlorine or bromine in presence of small quantities of red phosphorous to give exclusively a-chloro or a-bromo acids.
Example:
15. What is Hoffmann Bromamide Degradation Reaction?
Hoffmann Bromamide Degradation Reaction is a rearrangement reaction to form a primary amine from a primary amide. The resulting amine has one fewer carbon atom. The reaction was discovered by August Wilhelm von Hofmann.
Hoffmann Bromamide Reaction Mechanism
Questions on Hoffmann Bromamide Reaction
Ques. Hoffman bromide reaction involves the intermediate formation of which species?
Ans. A species with electron-deficient carbon is formed as an intermediate of the Hoffman bromide reaction.
Ques. In the Hofmann bromamide degradation reaction, the number of moles of NaOH and Br2 used per mole of amine produced are:
Ans. Four moles of NaOH and one mole of Br2
16. What is Kolbe’s Reaction?
Kolbe’s Reaction involves the heating of sodium phenoxide at 125oC with carbon dioxide under the pressure of 100 atm. It is then treated with sulfuric acid to produce aromatic hydroxy acid. The reaction was put forward by German chemist Hermann Kolbe.
Questions on Kolbe’s Reaction
Ques. What is the product of Kolbe's reaction?
Ans. The primary product of Kolbe’s reaction is Ortho-hydroxybenzoic acid (salicylic acid).
Ques. Which electrophile is used in Kolbe's reaction?
Ans. The electrophile that is used in Kolbe’s reaction is Carbon Dioxide.
17. What is Reimer-Tiemann Reaction?
Reimer-Tiemann Reaction involves the ortho-formylation of phenols. One of the examples is the conversion of phenol to salicylaldehyde. The reaction is named after Karl Reimer and Ferdinand Tiemann.
Reimer-Tiemann Reaction Mechanism
Questions on Reimer-Tiemann Reaction
Ques. What is the final product of the Reimer-Tiemann reaction?
Ans. The Reimer - Tiemann reaction involves the reaction of phenols in the presence of chloroform to obtain an aldehyde as the end product.
Ques. Is Reimer Tiemann an electrophilic substitution reaction?
Ans. The Reimer Tiemann reaction is an electrophilic substitution reaction mechanism. In the reaction, dichlorocarbene acts as an electrophile.
18. What is Rosenmund Reduction?
Rosenmund Reduction mechanism involves the selective reduction of an acyl chloride to an aldehyde. It is a hydrogenation process that was discovered by Karl Wilhelm Rosenmund.
Rosenmund Reduction Mechanism
Questions on Rosenmund Reduction
Ques. What is the catalyst in Rosenmund reduction?
Ans. The Rosenmund reduction uses modified palladium as a catalyst.
Ques. Why Sulphur is used in Rosenmund's reaction?
Ans. Sulfur is used in the Rosenmund reaction to prevent the subsequent hydrogenation of aldehyde.
19. What is Williamson Synthesis?
Williamson Synthesis mechanism involves the formation of ether from an organohalide and deprotonated alcohol (alkoxide). The reaction is named after Alexander Williamson.
Williamson Synthesis Mechanism
Questions on Williamson Synthesis
Ques. Why do we use RO– and Not ROH as the Nucleophile in Williamson synthesis?
Ans. The reaction of RO– with an alkyl halide is a faster reaction than the reaction of ROH. This is due to the higher electron density of oxygen, the nucleophile. Hence, we use RO–.
Ques. What are some limitations of the Williamson synthesis reaction?
Ans. The limitations of the reaction are as follows:
- Tertiary alkyl halides tend to undergo E2 elimination when alkoxide is present.
- Alkali phenoxides might undergo C-alkylation in addition to the expected O-alkylation.
20. What is Wolff-Kishner Reduction?
Wolff-Kishner Reduction mechanism involves the reduction of carbonyl functionalities into methylene groups. The reaction was put forward by Nicolai Kishner and Ludwig Wolff.
Wolff-Kishner Reduction Mechanism
Questions on Wolff-Kishner Reduction
Ques. Which reagent is used in Wolff-Kishner reduction?
Ans. NH2 – NH2 and KOH in ethylene glycol are used as reagents in Wolff Kishner reduction.
Ques. What will be formed when acetone undergoes Wolff Kishner reduction reaction?
Ans. The Wolff-Kishner reduction of acetone will give propane as the product.
21. What is Sandmeyer Reaction?
Sandmeyer Reaction mechanism involves the synthesis of aryl halides from aryl diazonium salts using copper salts as reagents or catalysts. The reaction was discovered by Traugott Sandmeyer.
Sandmeyer Reaction Mechanism
Questions on Sandmeyer Reaction
Ques. What is the importance of Sandmeyer’s reaction?
Ans. Sandmeyer’s reactions include reactions like cyanation, halogenation, and hydroxylation. It is important as it results in some substitution patterns that are not attainable by the direct substitution.
Ques. How will you prepare chlorobenzene by Sandmeyer reaction?
Ans. Chlorobenzene can be prepared by Sandmeyer’s reaction mechanism by treating benzene diazonium chloride with cuprous chloride that is dissolved in HCl.
22. What is Stephen Reaction?
Stephen Reaction, also known as Stephen Aldehyde Synthesis. The reaction mechanism involves the preparation of aldehydes from nitriles using tin (II) chloride, hydrochloric acid, and quenching iminium salt with water. One of the by-products of this reaction is ammonium chloride. The reaction was discovered by English chemist Stephen Henry.
Stephen Reaction Mechanism
Questions on Stephen Reaction
Ques. Which catalyst is used in Stephen's reaction?
Ans. SnCl2 or HCl is used as a catalyst in Stephen’s reaction.
Ques. Why is stannous chloride used in Stephen's reaction?
Ans. The reduction of nitriles with stannous chloride in hydrogen chloride in the ethyl acetate solvent leads to the production of an imine intermediate. The hydrolysis of this imine intermediate with water results in the production of the corresponding aldehyde.
23. What is Fischer Esterification?
In Fischer Esterification reaction mechanism, an ester is formed by the conversion of carboxylic acid in the presence of excess alcohol and a strong acid as catalysts. The reaction was discovered by Emil Fischer.
Fischer Esterification Mechanism
Questions on Fischer Esterification
Ques. What is the disadvantage of Fischer esterification?
Ans. Some disadvantages of the Fischer esterification reaction are:
- The thermodynamic reversibility of the reaction.
- The reaction rates are quite slow.
Ques. Does Fischer esterification need heat?
Ans. An energy source is usually needed to promote the Fischer esterification reaction. This energy is usually supplied in the form of heat.
24. What is Swartz Reaction?
Swartz Reaction mechanism involves the exchange of halogen atoms. The named reactions is basically used to get alkyl fluorides from alkyl bromides or alkyl chlorides.
Swartz Reaction Mechanism
Questions on Swartz's Reaction
Ques. Which reagent is used in Swartz reaction?
Ans. A mixture of antimony trifluoride and chlorine (SbF3 + Cl2) is used as a reagent in Swartz reaction.
Ques. Why NaF is not used in Swarts reaction?
Ans. If NaF is used instead of transition metals fluoride in Swarts reaction with chloroalkane, NaCl is obtained with fluoro alkane. However, NaCl is very soluble in a water solvent. Besides, the formation of the C–F bond can be explosive.
25. What is Haloform Reaction?
The Haloform reaction mechanism involves the exhaustive halogenation of methyl aldehyde or methyl ketone in the presence of a base.
Haloform Reaction Mechanism
Questions on Haloform Reaction
Ques. What is known as haloform?
Ans. Trihalogen compounds that are derived from methane are known as haloforms, such as chloroform CHCl3, bromoform CHBr3 and iodoform CHI3.
Ques. What is the equation of Haloform reaction?
Ans. 
26. What is Grignard Synthesis?
Grignard Synthesis mechanism involves the addition of alkyl, vinyl, allyl, and aryl-magnesium halides to a carbonyl group in an aldehyde or ketone. It is named after French chemist Francois Auguste Victor Grignard.
Grignard Synthesis Mechanism
Questions on Grignard Synthesis
Ques. Why must Grignard reaction be anhydrous?
Ans. The Grignard reagent reacts readily with water to form alkanes, therefore the reaction conditions for the Grignard reaction should be anhydrous.
Ques. Why is magnesium used in the Grignard reaction?
Ans. The magnesium metal is used in the Grignard synthesis reaction as it contains a layer of oxide on the surface that helps in preventing it from reacting with the alkyl bromide.
List of Other Named Reactions Mechanisms
Other named reactions that are considered important in organic chemistry are:
These mechanisms of named reactions can be used to name the type of reaction, name the reagents used in the reactions, and understand the formation of new organic compounds.
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