Chemca
The Blueprint: 70 Name Reactions
The ultimate dictionary of synthetic organic chemistry. These 70 named reactions form the absolute foundation of Class 11, 12, JEE Advanced, and NEET chemistry. Click any reaction to reveal its mechanism summary, reagents, and balanced chemical equation.
Part 1: Haloalkanes, Haloarenes & Hydrocarbons
1.Wurtz Reaction
Description: Alkyl halides react with sodium in dry ether to form higher alkanes containing double the number of carbon atoms. It proceeds via a free-radical mechanism.
2.Fittig Reaction
Description: The aromatic analog of the Wurtz reaction. Aryl halides react with sodium in dry ether to yield diaryls (e.g., biphenyl).
3.Wurtz-Fittig Reaction
Description: A mixture of an alkyl halide and an aryl halide reacts with sodium in dry ether to form an alkylbenzene.
4.Finkelstein Reaction
Description: Alkyl iodides are prepared by reacting alkyl chlorides/bromides with NaI in dry acetone. The forward reaction is driven by the precipitation of NaCl/NaBr in acetone.
5.Swarts Reaction
Description: The best method to synthesize alkyl fluorides. Heating an alkyl chloride/bromide in the presence of heavy metal fluorides (AgF, Hg2F2, CoF2, or SbF3).
6.Sandmeyer Reaction
Description: The diazonium group is replaced by Cl, Br, or CN using cuprous salts (Cu2Cl2, Cu2Br2, CuCN). Yields are generally high.
7.Gattermann Reaction
Description: A modification of the Sandmeyer reaction using freshly prepared copper powder in the presence of HX instead of cuprous salts.
8.Balz-Schiemann Reaction
Description: Synthesis of fluorobenzene. Diazonium chloride reacts with fluoroboric acid to precipitate diazonium fluoroborate, which on heating yields fluorobenzene.
9.Borodine-Hunsdiecker Reaction
Description: Silver salts of carboxylic acids react with bromine in refluxing CCl4 to form alkyl bromides with one less carbon atom.
10.Friedel-Crafts Alkylation
Description: Introduction of an alkyl group into a benzene ring using an alkyl halide and a Lewis acid catalyst.
11.Friedel-Crafts Acylation
Description: Introduction of an acyl group (R-CO-) into a benzene ring using an acyl halide or acid anhydride and a Lewis acid catalyst.
12.Corey-House Synthesis
Description: An excellent method for preparing unsymmetrical alkanes. A lithium dialkylcopper (Gilman reagent) reacts with an alkyl halide.
13.Kolbe's Electrolysis
Description: Electrolysis of an aqueous solution of sodium/potassium salt of a carboxylic acid yields an alkane containing an even number of carbon atoms at the anode.
14.Kharasch Effect (Peroxide Effect)
Description: Addition of HBr to unsymmetrical alkenes in the presence of organic peroxides yields the anti-Markovnikov product via a free radical mechanism (only works with HBr).
Part 2: Alcohols, Phenols & Ethers
15.Dow Process
Description: Chlorobenzene is fused with NaOH at extremely high temperature and pressure to form sodium phenoxide, which is acidified to yield phenol.
16.Cumene Process
Description: Isopropylbenzene (cumene) is oxidized by air to cumene hydroperoxide, which is cleaved by dilute acid to yield Phenol and Acetone (valuable byproduct).
17.Kolbe-Schmitt Reaction
Description: Sodium phenoxide is heated with CO2 under pressure. Electrophilic aromatic substitution yields sodium salicylate, which on acidification gives Salicylic Acid.
18.Reimer-Tiemann Reaction
Description: Phenol reacts with chloroform in the presence of NaOH. A dichlorocarbene intermediate attacks the ring, ultimately yielding Salicylaldehyde (o-hydroxybenzaldehyde).
19.Williamson Ether Synthesis
Description: The best laboratory method for symmetrical and unsymmetrical ethers. An alkoxide ion nucleophilically attacks a primary alkyl halide.
20.Hydroboration-Oxidation
Description: Addition of borane to an alkene followed by oxidation with hydrogen peroxide in alkaline medium. Yields alcohols with anti-Markovnikov regioselectivity and syn-stereoselectivity.
21.Oxymercuration-Demercuration
Description: Alkenes react with mercuric acetate and water, followed by reduction with NaBH4. Yields Markovnikov alcohols without carbocation rearrangement.
Part 3: Aldehydes & Ketones
22.Rosenmund Reduction
Description: Acid chlorides are catalytically reduced to aldehydes. BaSO4 acts as a poison to prevent further reduction to alcohols.
23.Stephen Reaction
Description: Nitriles are reduced to imine hydrochlorides by stannous chloride in HCl, which upon hydrolysis yield aldehydes.
24.Etard Reaction
Description: Toluene is oxidized directly to benzaldehyde using chromyl chloride, forming a brown chromium complex that is then hydrolyzed.
25.Gattermann-Koch Reaction
Description: Benzene reacts with carbon monoxide and hydrogen chloride in the presence of anhydrous AlCl3 to yield benzaldehyde.
26.Clemmensen Reduction
Description: The carbonyl group of aldehydes and ketones is reduced directly to a methylene group (-CH2-) using zinc amalgam and concentrated HCl.
27.Wolff-Kishner Reduction
Description: The carbonyl group is converted to a hydrazone, which upon heating with a strong base (KOH) in ethylene glycol decomposes to yield an alkane and nitrogen gas.
28.Aldol Condensation
Description: Two molecules of an aldehyde/ketone having at least one $\alpha$-hydrogen condense in the presence of dilute alkali to form a $\beta$-hydroxy aldehyde/ketone (aldol/ketol), which easily dehydrates to an $\alpha,\beta$-unsaturated compound.
29.Cross-Aldol Condensation
Description: An aldol condensation carried out between two different aldehydes or ketones. If both have $\alpha$-hydrogens, a complex mixture of 4 products is obtained.
30.Cannizzaro Reaction
Description: Aldehydes lacking $\alpha$-hydrogens (like benzaldehyde or formaldehyde) undergo self-oxidation-reduction on heating with conc. alkali, yielding a primary alcohol and a carboxylic acid salt.
31.Cross-Cannizzaro Reaction
Description: A Cannizzaro reaction between two different aldehydes lacking $\alpha$-hydrogens. The more reactive aldehyde (always Formaldehyde, if present) is oxidized to formate, while the other is reduced.
32.Haloform (Iodoform) Reaction
Description: Compounds with a $\ce{CH3-CO-}$ group (or those oxidizable to it) react with halogens in alkali to yield a haloform ($\ce{CHX3}$). Iodoform ($\ce{CHI3}$) is a yellow precipitate.
33.Tishchenko Reaction
Description: All aldehydes (with or without $\alpha$-H) undergo disproportionation in the presence of aluminum ethoxide. The resulting alcohol and acid immediately combine to form an ester.
Part 4: Carboxylic Acids, Amines & Beyond
34.Hell-Volhard-Zelinsky (HVZ) Reaction
Description: Carboxylic acids having $\alpha$-hydrogens are halogenated at the $\alpha$-position on treatment with chlorine or bromine in the presence of small amounts of red phosphorus.
35.Gabriel Phthalimide Synthesis
Description: Used for the preparation of pure primary aliphatic amines. Phthalimide is converted to its potassium salt, alkylated with RX, and then hydrolyzed.
36.Hoffmann Bromamide Degradation
Description: Primary amides are converted to primary amines containing one less carbon atom using bromine and an aqueous/ethanolic solution of sodium or potassium hydroxide.
37.Carbylamine Reaction
Description: Primary aliphatic and aromatic amines on heating with chloroform and ethanolic KOH form isocyanides (carbylamines) which have extremely foul smells.
38.Hinsberg's Reaction
Description: Benzene sulfonyl chloride reacts with $1^\circ$ amines to give alkali-soluble sulfonamides, and with $2^\circ$ amines to give alkali-insoluble sulfonamides. $3^\circ$ amines do not react.
39.Coupling Reaction (Azo Dyes)
Description: Arenediazonium salts react with highly activated rings (phenols, anilines) to form intensely colored azo compounds ($-N=N-$) used as dyes.
40.Schotten-Baumann Reaction
Description: The benzoylation of compounds containing active hydrogen (like phenols or primary/secondary amines) using benzoyl chloride in the presence of dilute aqueous NaOH.
41.Mendius Reduction
Description: The catalytic or chemical reduction of alkyl cyanides (nitriles) to primary amines using Sodium amalgam in ethanol (or $\ce{LiAlH4}$).
42.Sabatier-Senderens Reduction
Description: The catalytic hydrogenation of unsaturated hydrocarbons (alkenes or alkynes) into alkanes using hydrogen gas over a heated Nickel catalyst.
43.Lindlar's Catalytic Reduction
Description: Controlled partial reduction of an alkyne to a cis-alkene using Hydrogen gas over a poisoned palladium catalyst (Lindlar's catalyst).
44.Birch Reduction
Description: Partial reduction of alkynes to trans-alkenes, or the partial reduction of aromatic rings to 1,4-cyclohexadienes, using alkali metals in liquid ammonia.
45.Ullmann Reaction
Description: The synthesis of biaryls (like biphenyl) from aryl halides (specifically iodides) by heating with copper powder in a sealed tube.
46.Hofmann Mustard Oil Reaction
Description: Primary amines react with carbon disulfide to form a dithiocarbamic acid, which on heating with $\ce{HgCl2}$ gives an alkyl isothiocyanate with a pungent mustard oil smell.
47.Tollens' Reagent Oxidation
Description: Aldehydes are oxidized to carboxylates by Tollens' reagent, a mild oxidizing agent, while reducing the silver ions to form a metallic silver mirror.
48.Fehling's Solution Oxidation
Description: Aliphatic aldehydes reduce the blue $\ce{Cu^2+}$ complex in Fehling's solution to insoluble red-brown Cuprous oxide ($\ce{Cu2O}$).
49.Gattermann Aldehyde Synthesis
Description: Formylation of aromatic rings (especially phenols and ethers) using a mixture of hydrogen cyanide and hydrogen chloride with a Lewis acid catalyst.
50.Blanc Chloromethylation
Description: Introduction of a chloromethyl group ($\ce{-CH2Cl}$) into an aromatic ring using formaldehyde, hydrogen chloride, and a Lewis acid catalyst (ZnCl2).
Part 5: Advanced JEE & NEET Exclusives
51.Wittig Reaction
Description: Aldehydes or ketones react with a phosphorus ylide (alkylidenephosphorane) to yield an alkene and triphenylphosphine oxide. It allows highly regioselective placement of the double bond.
52.Perkin Reaction
Description: Condensation of an aromatic aldehyde with an aliphatic acid anhydride in the presence of the alkali salt of the corresponding acid to yield an $\alpha,\beta$-unsaturated aromatic acid.
53.Reformatsky Reaction
Description: Condensation of an aldehyde or ketone with an $\alpha$-halo ester in the presence of metallic zinc to form a zinc enolate intermediate, followed by hydrolysis to yield a $\beta$-hydroxy ester.
54.Benzoin Condensation
Description: Two molecules of an aromatic aldehyde lacking $\alpha$-hydrogens condense in the presence of an alkali cyanide catalyst to form an $\alpha$-hydroxy ketone (benzoin).
55.Claisen Condensation
Description: Two molecules of an ester containing $\alpha$-hydrogens undergo a condensation reaction in the presence of a strong base (like sodium ethoxide) to form a $\beta$-keto ester.
56.Dieckmann Condensation
Description: The intramolecular version of the Claisen condensation. A diester reacts with a base to form a cyclic $\beta$-keto ester (typically forming 5- or 6-membered rings).
57.Pinacol-Pinacolone Rearrangement
Description: Conversion of a fully substituted 1,2-diol (pinacol) to a ketone (pinacolone) under acidic conditions, involving a 1,2-alkyl shift to form a resonance-stabilized oxocarbenium ion.
58.Beckmann Rearrangement
Description: Rearrangement of an oxime to a substituted amide under strongly acidic conditions (e.g., $H_2SO_4, PCl_5, SOCl_2$). The group anti (trans) to the leaving hydroxyl group migrates to the nitrogen.
59.Baeyer-Villiger Oxidation
Description: Oxidation of a ketone to an ester (or cyclic ketone to a lactone) using a peroxyacid (like mCPBA or peracetic acid). Oxygen inserts adjacent to the carbonyl, favoring migration of the more substituted alkyl group.
60.Curtius Rearrangement
Description: Thermal decomposition of an acyl azide forms an isocyanate intermediate via migration of the alkyl group. Subsequent hydrolysis yields a primary amine with one less carbon atom.
61.Schmidt Reaction
Description: Reaction of a carboxylic acid with hydrazoic acid ($HN_3$) in the presence of strong acid ($H_2SO_4$) to yield a primary amine with the loss of $CO_2$ and $N_2$.
62.Hofmann Elimination
Description: Elimination of a quaternary ammonium hydroxide upon strong heating. It highly favors the formation of the less substituted (least stable) alkene, known as the Hofmann product, due to severe steric bulk of the leaving group.
63.Cope Elimination
Description: A concerted, intramolecular syn-elimination of an amine N-oxide upon heating to form an alkene and an N,N-dialkylhydroxylamine. It also favors the Hofmann product.
64.Michael Addition
Description: Nucleophilic addition of a carbanion (typically an enolate from an active methylene compound) to the $\beta$-carbon of an $\alpha,\beta$-unsaturated carbonyl compound.
65.Robinson Annulation
Description: A powerful two-step process to form a six-membered ring. It consists of a Michael addition followed immediately by an intramolecular Aldol condensation and dehydration.
66.Stork Enamine Synthesis
Description: Ketones are converted to enamines (using $2^\circ$ amines), which then act as mild, neutral carbon nucleophiles for alkylation, acylation, or Michael addition. Hydrolysis regenerates the ketone.
67.Darzens Condensation
Description: Condensation of a ketone or aldehyde with an $\alpha$-halo ester in the presence of a base to form an $\alpha,\beta$-epoxy ester (glycidic ester).
68.Meerwein-Ponndorf-Verley (MPV) Reduction
Description: A highly chemoselective reduction of ketones to secondary alcohols using aluminum isopropoxide in excess isopropanol. It does not reduce double bonds or ester groups.
69.Oppenauer Oxidation
Description: The exact reverse of the MPV reduction. Mild and highly chemoselective oxidation of secondary alcohols to ketones using aluminum tert-butoxide in excess acetone.
70.Bouveault-Blanc Reduction
Description: The chemical reduction of esters to primary alcohols using a dissolving metal reduction system (sodium metal in ethanol). Pre-dates the use of $LiAlH_4$.
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