Important Organic Name Reactions
The following reactions are categorized by their primary function or mechanism, drawn directly from the provided chemical reaction sources.
1. Condensation and Carbonyl Addition Reactions
- Aldol Condensation
- Two molecules of aldehydes or ketones containing an α-hydrogen condense in the presence of a base (like dilute NaOH) to form β-hydroxyaldehyde or β-hydroxyketone.
- Claisen-Schmidt Reaction
- A base-catalyzed crossed aldol condensation where an aromatic aldehyde condenses with an aliphatic aldehyde or ketone.
- Cannizzaro Reaction
- Aldehydes lacking an α-hydrogen atom undergo self-oxidation and reduction (disproportionation) in the presence of concentrated alkali to form an alcohol and a carboxylic acid salt.
- Claisen Condensation
- Esters containing α-hydrogen atoms undergo self-condensation in the presence of a strong base (like sodium ethoxide) to yield β-keto esters.
- Perkin Condensation
- An aromatic aldehyde condenses with an aliphatic acid anhydride in the presence of the sodium salt of the same acid to yield an α,β-unsaturated acid (e.g., Cinnamic acid).
- Knoevenagel Reaction
- Aldehydes and ketones condense with compounds containing active methylene groups (like malonic acid) to form α,β-unsaturated compounds.
- Reformatsky Reaction
- Zinc and an α-halogenated ester react with a carbonyl compound to yield a β-hydroxy ester.
- Wittig Reaction
- A carbonyl compound is treated with a phosphorous ylide to form an alken.
2. Reduction Reactions
- Clemmensen Reduction
- Aldehydes and ketones are reduced to alkanes using Zinc-Mercury amalgam (Zn-Hg) and concentrated HCl.
- Wolff-Kishner Reduction
- Aldehydes and ketones are reduced to alkanes by heating with hydrazine (NH2NH2) and KOH .
- Rosenmund’s Reduction
- Acid chlorides are reduced to aldehydes using hydrogen and palladised barium sulphate poisoned with sulphur or quinoline.
- Birch Reduction
- Disubstituted alkynes are reduced with sodium in liquid ammonia to predominantly give trans-alkenes.
- Meerwein-Ponndorf-Verley (MPV) Reduction
- Ketones are reduced to secondary alcohols by heating with isopropyl alcohol and aluminium isopropoxide.
- Stephen’s Reduction
- Cyanides are reduced to aldehydes using SnCl2/HCl followed by hydrolysis.
- Sabatier-Senderen’s Reaction
- Unsaturated hydrocarbons (alkenes/alkynes) are reduced to alkanes using a nickel catalyst.
3. Oxidation Reactions
- Etard Reaction
- Aromatic hydrocarbons (like toluene) are oxidized by chromyl chloride (CrO2Cl2) to yield aldehydes.
- Oppenauer’s Oxidation
- Secondary alcohols are oxidized to ketones using aluminium tert-butoxide in excess acetone.
- Hydroboration-Oxidation
- Alkenes react with diborane followed by oxidation with hydrogen peroxide/hydroxide to form alcohols.
- Wacker Process
- Alkenes are directly oxidized to aldehydes or ketones by PdCl2-CuCl2 in the presence of air or oxygen.
- Tischenko Reaction
- Aldehydes undergo simultaneous oxidation and reduction in the presence of aluminium ethoxide to form an ester.
- Ozonolysis
- Alkenes are oxidized by ozone to form an unstable ozonide, which reduces to aldehydes or ketones depending on the structure.
4. Synthesis and Coupling Reactions
- Wurtz Reaction
- Alkyl halides react with sodium in dry ether to form alkanes.
- Wurtz-Fittig Reaction
- A mixture of aryl halide and alkyl halide reacts with sodium to form substituted arenes.
- Frankland Reaction
- Similar to the Wurtz reaction, but uses Zinc instead of Sodium to react with alkyl halides to form alkanes.
- Finkelstein Reaction
- Alkyl chlorides or bromides are treated with sodium iodide in acetone to prepare iodoalkanes.
- Friedel-Crafts Reaction
- Aromatic hydrocarbons react with alkyl halides in the presence of a Lewis acid (like AlCl3) to form substituted hydrocarbons.
- Sandmeyer’s Reaction
- Diazonium salts react with CuCl/HCl or CuBr/HBr to form aryl halides.
- Gattermann-Koch Reaction
- Benzene reacts with CO and HCl in the presence of AlCl3 to form benzaldehyde.
- Kolbe’s Electrolytic Method
- Electrolysis of carboxylic acid salts yields higher alkanes.
- Corey-House Synthesis
- An alkyl halide is converted to lithium dialkyl cuprate and then reacted with another alkyl halide to give an alkane.
- Ullmann Reaction
- Aryl iodides react with copper metal to yield biphenyls .
- Williamson’s Synthesis
- Metal alkoxides react with alkyl halides to yield ethers .
- Gabriel Phthalimide Synthesis
- Phthalimide is converted to N-alkyl phthalimide, which is then hydrolysed to yield primary amines .
- Reimer-Tiemann Reaction
- Phenol reacts with chloroform and alkali to yield salicylaldehyde.
- Oxo Process
- Alkenes are heated with water gas (CO + H2) and a cobalt catalyst to yield aldehydes.
- Wohler’s Reaction
- Calcium carbide reacts with water to prepare acetylene .
5. Rearrangement and Elimination Reactions
- Beckmann Rearrangement
- Oximes rearrange in the presence of acid catalysts to form substituted amides.
- Hofmann-Bromamide Reaction
- Primary amides react with bromine and alkali to yield primary amines with one less carbon atom .
- Curtius Rearrangement
- Acyl azides allow for the formation of primary amines via an isocyanate intermediate.
- Fries Rearrangement
- Phenyl esters heated with anhydrous AlCl3 rearrange to form ortho- or para-hydroxyketones .
- Cope Elimination
- Tertiary amine oxides containing a β-hydrogen form an alkene upon heating.
- Schmidt’s Reaction
- Carboxylic acids react with hydrazoic acid (HN3) to produce primary amines.
6. Halogenation and Other Specific Reactions
- Haloform Reaction
- Methyl ketones oxidize with sodium hypohalite to yield haloform and a carboxylic acid salt .
- Hell-Volhard-Zelinsky (HVZ) Reaction
- Carboxylic acids react with bromine/chlorine and red phosphorus to produce α-haloacids.
- Hunsdiecker Reaction
- Silver salts of carboxylic acids react with bromine to yield alkyl bromides with one less carbon atom.
- Balz-Schiemann’s Reaction
- Benzene diazonium salt is converted to fluorobenzene via tetrafluoroborate.
- Carbylamine Reaction
- Primary amines are heated with chloroform and alcoholic KOH to form foul-smelling isocyanides.
- Hofmann Mustard Oil Reaction
- A test for primary amines where the reaction yields alkyl isothiocyanates which smell like mustard oil.
- Schotten-Baumann Reaction
- The benzoylation of alcohols or phenols in the presence of NaOH.
- Diels-Alder Reaction
- A conjugated diene adds to a dienophile to form a cyclic system.
- Leuckart Reaction
- Aldehydes or ketones undergo reductive amination with ammonium formate to yield primary amines.