Named Reactions in Organic Chemistry for JEE Main

Named reactions encode the most important organic transformations, and JEE Main regularly asks for their products, reagents, or mechanisms. Rather than memorising them as isolated facts, understanding the logic of each reaction — what bond forms, why that reagent works — builds a network of knowledge that handles unfamiliar derivatives. This guide covers every named reaction the JEE syllabus includes.

Carbonyl and Aldehyde Named Reactions

Aldol condensation: two molecules of an aldehyde (or ketone) with α-H react in base to give β-hydroxy carbonyl compound (aldol), which can dehydrate to α,β-unsaturated carbonyl. Cannizzaro reaction: aldehydes without α-H (formaldehyde, benzaldehyde) in concentrated NaOH disproportionate — one molecule oxidises to acid, another reduces to alcohol. Clemmensen reduction (Zn-Hg/HCl): converts carbonyl to CH₂ under acidic conditions. Wolff-Kishner reduction (NH₂NH₂/KOH): converts carbonyl to CH₂ under basic conditions. These four are among the most-tested in every JEE paper. See our aldehydes and ketones guide for the broader context.

Benzene and Phenol Named Reactions

Reimer-Tiemann reaction: phenol + CHCl₃ + KOH → salicylaldehyde (−CHO is introduced ortho). Kolbe–Schmitt reaction: sodium phenoxide + CO₂ under pressure → salicylic acid. Friedel-Crafts alkylation: benzene + R-Cl/AlCl₃ → alkylbenzene. Friedel-Crafts acylation: benzene + R-COCl/AlCl₃ → phenyl ketone. Gattermann-Koch reaction: benzene + CO + HCl/AlCl₃, CuCl → benzaldehyde. Memorise the product and the unique reagent for each; the reagent alone often identifies the reaction.

Amine and Nitrogen Named Reactions

Hofmann degradation (rearrangement): primary amide + Br₂/NaOH → primary amine with one fewer carbon. Gabriel synthesis: phthalimide + alkyl halide (SN2) → primary amine (no secondary or tertiary products). Sandmeyer reaction: aryl diazonium + CuCN → aryl nitrile; + CuBr → aryl bromide; + CuCl → aryl chloride. Balz-Schiemann reaction: diazonium + HBF₄ → aryl fluoride. Gomberg-Bachmann: diazonium + benzene/NaOH → biaryl.

Rearrangement Reactions

Beckmann rearrangement: oxime of ketone + H₂SO₄ → lactam (cyclic amide). The group anti to the hydroxyl migrates. Pinacol-Pinacolone rearrangement: vicinal diol + acid → carbonyl compound via 1,2-shift. Baeyer-Villiger oxidation: ketone + peracid → ester (the more substituted group migrates to oxygen). Recognising rearrangements is a sophisticated JEE skill — they involve migration of a group to an adjacent electron-deficient centre.

Halogens and Miscellaneous

Hell-Volhard-Zelinsky: carboxylic acid + Br₂/P → α-bromo acid. Rosenmund reduction: acyl chloride + H₂/Pd-BaSO₄ → aldehyde (catalyst poisoned to prevent over-reduction). Etard reaction: toluene + CrO₂Cl₂ → benzaldehyde. Stephen reaction: nitrile + SnCl₂/HCl → aldehyde. After learning all named reactions, practise identifying them from a given set of reagents, then take a free mock test on organic chemistry. For the broader reaction mechanisms see our reaction mechanisms guide.