Sandmeyer’s Reaction - Benzene diazonium chloride is converted to chlorobenzene, bromobenzene, cyanobenzene on treatment with CuCl/HCl, CuBr/HBr and CuCN/KCN, respectively.
Finkelstein Reaction - Chloroalkanes or bromoalkanes are converted into corresponding iodoalkanes by treating with sodium iodide dissolved in acetone.
Wurtz Reaction - Alkyl halides react with metallic sodium in the presence of dry ether to form alkanes. This reaction is used for the preparation of higher alkanes.
Wurtz–Fittig Reaction - Aryl halides when treated with alkyl halide and sodium in dry ether give alkylbenzenes.
Fittig’s Reaction - In this reaction two molecules of haloarene combine with metallic sodium in the presence of dry ether to give diphenyl or biphenyl.
Friedel–Crafts Alkylation - Benzene and other aromatic compounds react with alkyl halides in the presence of anhydrous AlCl3 to form alkyl benzene.
Dow’s Process - When chlorobenzene is treated with an aqueous solution of NaOH at 623 K, 300 atm pressure sodium phenoxide is formed which on acidification gives phenol.
Hunsdiecker’s Reaction - Bromoalkanes are obtained by this method by refluxing silver salts of fatty acids with Br2 in CCl4.
Note- This method can be employed to decrease the number of carbon atoms.
Kolbe’s reaction - When sodium phenoxide is heated with CO2 at 400 K under a pressure of 4 –7 atm, the resulting product on acidification yields salicylic acid.
Reimer–Tiemann reaction - Treatment of phenol with chloroform in the presence of sodium hydroxide followed by hydrolysis of resulting product gives o-hydroxybenzaldehyde (salicylaldehyde) as a major product.
Williamson synthesis - It consists of reacting an alkyl halide with sodium alkoxide or sodium phenoxide to form ether.
Rosenmund Reduction - Acid chloride are converted to corresponding aldehydes by catalytic reduction. The reaction is carried out by passing H2 gas through a hot solution of acid chloride in the presence of Pd deposited over BaSO4 (partially poisoned with sulphur or quinoline).
Stephen reaction - Nitriles are reduced to corresponding imines with SnCl2 in the presence of hydrochloric acid, which on hydrolysis give corresponding aldehyde.
Etard reaction - Chromyl chloride oxidises toluene to chromium complex which on hydrolysis gives benzaldehyde.
Gatterman–Koch reaction - When benzene or its derivative is treated with carbon monoxide and hydrogen chloride in the presence of anhydrous AlCl3 and CuCl, it gives benzaldehyde or substituted benzaldehyde.
Friedel–Crafts alkylation - Benzene and other aromatic compounds react with alkyl halides in the presence of anhydrous AlCl3 to form alkyl benzenes.
Friedel–Crafts acylation - Benzene and other aromatic compounds react with acylchlorides or acid anhydrides in the presence of anhyd. AlCl3 to form aromatic ketone.
Clemmensen reduction - The carbonyl group of aldehydes and ketones is reduced to CH2 group on treatment with zinc amalgam and concentrated hydrochloric acid.
Wolff–Kishner reduction - The carbonyl group of aldehydes and ketones is reduced to —CH2 group on treatment with hydrazine followed by heating with potassium or sodium hydroxide in a high boiling solvent such as ethylene glycol.
Aldol condensation - Two molecules of aldehydes or ketones containing at least one a-hydrogen atom on treatment with dilute alkali undergo condensation to form b-hydroxy aldehydes (aldol) or b-hydroxy ketones (Ketol).
Cross aldol condensation - When aldol condensation is carried out between two different aldehydes and/or ketones, it is called cross aldol condensation.
Cannizzaro reaction - Aldehydes which do not have an a-hydrogen, undergo self oxidation and reduction (disproportionation) reaction on treatment with concentrated alkali. In this reaction, one molecule of the aldehyde is reduced to alcohol while another is oxidised to carboxylic acid salt.
Hell-Volhard-Zelinsky reaction - Carboxylic acids having an a-hydrogen are halogenated at the α-position on treatment with chlorine, or bromine in the presence of red phosphorus to give a-halocarboxylic acids.
Gabriel phthalimide synthesis - This reaction is used for the preparation of aliphatic primary amines. In this reaction, phthalimide is first of all treated with ethanolic KOH to form potassium phthalimide. Potassium phthalimide on treatment with alkyl halide gives N-alkyl phthalimide, which on hydrolysis with dilute hydrochloric acid gives a primary amine as the product.
Hoffmann bromamide reaction - When a primary acid amide is heated with an aqueous or ethanolic solution of NaOH or KOH and bromine (i.e., NaOBr or KOBr), it gives a primary amine with one carbon atom less.
Sandmeyer’s reaction - The Cl– , Br– and CN– nucleophiles can easily be introduced in the benzene in the presence of Cu (I) ion. This reaction is called Sandmeyer’s reaction.