Oxidation Of Secondary Alcohols To Ketones - Wikipedia

Chemical reaction

Alcohol oxidation is a collection of oxidation reactions in organic chemistry that convert alcohols to aldehydes, ketones, carboxylic acids, and esters. The reaction mainly applies to primary and secondary alcohols. Secondary alcohols form ketones, while primary alcohols form aldehydes or carboxylic acids.[1]

A variety of oxidants can be used.

Almost all industrial scale oxidations use oxygen or air as the oxidant.[2]

Through a variety of mechanisms, the removal of a hydride equivalent converts a primary or secondary alcohol to an aldehyde or ketone, respectively. The oxidation of primary alcohols to carboxylic acids normally proceeds via the corresponding aldehyde, which is transformed via an aldehyde hydrate (gem-diol, R-CH(OH)2) by reaction with water. Thus, the oxidation of a primary alcohol at the aldehyde level without further oxidation to the carboxylic acid is possible by performing the reaction in absence of water, so that no aldehyde hydrate can be formed.

To aldehydes and ketones

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In industry

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The largest operations involve the oxidation of methanol and ethanol to formaldehyde and acetaldehyde, which are produced on million ton scale annually. Both processes use O2 as the oxidant. Methanol oxidation employs a molybdenum oxide-based catalyst. Other large scale aldehydes and ketones are produced by autoxidation of hydrocarbons: benzaldehyde from toluene, acrolein from propylene, acetone from cumene, cyclohexanone from cyclohexanol.[2]

Laboratory

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In teaching laboratories and small scale operations, many reagents have been developed for the oxidation of secondary alcohols to ketones and primary alcohols to aldehydes. Allylic and benzylic alcohols are especially prone to oxidation. Aldehydes are susceptible to over oxidation to carboxylic acids.

Chromium(VI) reagents

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Chromium(VI) reagents are commonly used for these oxidations. One family of Cr(VI) reagents employs the complex CrO3(pyridine)2.[3]

• Sarett's reagent: a solution of CrO3(pyridine)2 in pyridine. It was popularized for selective oxidation of primary and secondary alcohols to carbonyl compounds.
• Collins reagent is a solution of the same CrO3(pyridine)2 but in dichloromethane. The Ratcliffe variant of Collins reagent relates to details of the preparation of this solution, i.e., the addition of chromium trioxide to a solution of pyridine in methylene chloride.[4]

A second family of Cr(VI) reagents are salts, featuring the pyridinium cation (C5H5NH+).

• pyridinium dichromate (PDC) is the pyridium salt of dichromate, [Cr2O7]2-.
• pyridinium chlorochromate (PCC) is the pyridinium salt of [CrO3Cl]−.

These salts are less reactive, more easily handled, and more selective than Collins reagent in oxidations of alcohols.

The above reagents represent improvements over the older Jones reagent, a solution of chromium trioxide in aqueous sulfuric acid.

Dess–Martin and related oxidations

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The Dess–Martin periodinane is a mild oxidant for the conversion of alcohols to aldehydes or ketones.[5] The reaction is performed under standard conditions, at room temperature, most often in dichloromethane. The reaction takes between half an hour and two hours to complete. The product is then separated from the spent periodinane.[6] Many iodosyl-based oxidants have been developed, e.g. IBX.

Swern oxidation

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Swern oxidation uses oxalyl chloride, dimethylsulfoxide, and an organic base, such as triethylamine.

The by-products are dimethyl sulfide (Me2S), carbon monoxide (CO), carbon dioxide (CO2) and – when triethylamine is used as base – triethylammonium chloride (C6H15NHCl).

The related N-tert-Butylbenzenesulfinimidoyl chloride combines both the sulfur(IV), the base, and the activating Lewis acid in one molecule.

Oppenauer oxidation

[edit] Main article: Oppenauer oxidation

This seldom-used method interconverts alcohols and carbonyls.

Niche methods

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Ley oxidation uses NMO as the stoichiometric oxidant with tetrapropylammonium perruthenate as a catalyst.

Fétizon oxidation, also a seldom-used method, uses silver carbonate supported on Celite. This reagent operates through single electron oxidation by the silver cations.

Another method is the oxoammonium-catalyzed oxidation. TEMPO exhibits a strong, pH-dependent selectivity for either primary or secondary alcohols; but the effect is primarily steric and other N-oxides behave differently.

Additionally, sodium hypochlorite (or household bleach) in acetone has been reported for efficient conversion of secondary alcohols in the presence of primary alcohols (Stevens oxidation).[7]

Soluble transition metal complexes catalyze the oxidation of alcohols by presence of dioxygen or another terminal oxidant.[8]

Oxidation of diols

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The largest scale oxidation of 1,2-diols gives glyoxal from ethylene glycol. The conversion uses air or sometimes nitric acid.[2]

In the laboratory, vicinal diols suffer oxidative breakage at a carbon-carbon bond with some oxidants such as sodium periodate (NaIO4), (diacetoxyiodo)benzene (PhI(OAc)2)[9] or lead tetraacetate (Pb(OAc)4), resulting in generation of two carbonyl groups. The reaction is also known as glycol cleavage.

To carboxylic acids

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In industry

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The oxidation of primary alcohols to carboxylic acids can be carried out using a variety of reagents, but O2/air and nitric acid dominate as the oxidants on a commercial scale. Large scale oxidations of this type are used for the conversion of cyclohexanol alone or as a mixture with cyclohexanone to adipic acid. Similarly cyclododecanol is converted to the 12-carbon dicarboxylic acid. 3,5,5-Trimethylcyclohexanol is similarly oxidized to trimethyladipic acid.[2]

Many specialty reagents have been developed for laboratory scale oxidations of alcohols to carboxylic acids.

Potassium permanganate

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Potassium permanganate (KMnO4) oxidizes primary alcohols to carboxylic acids very efficiently. This reaction, which was first described in detail by Fournier,[10][11] is typically carried out by adding KMnO4 to a solution or suspension of the alcohol in an alkaline aqueous solution. For the reaction to proceed efficiently, the alcohol must be at least partially dissolved in the aqueous solution. This can be facilitated by the addition of an organic co-solvent such as dioxane, pyridine, acetone or t-BuOH. KMnO4 reacts with many functional groups, such as secondary alcohols, 1,2-diols, aldehydes, alkenes, oximes, sulfides and thiols, and carbon-carbon double bonds. Thus, selectivity is an issue.

Jones oxidation

[edit] Main article: Jones oxidation

The so-called Jones reagent, prepared from chromium trioxide (CrO3) and aqueous sulfuric acid, oxidizes alcohols to a carboxylic acid. The protocol frequently affords substantial amounts of esters.[13] Problems are the toxicity and environmental unfriendliness of the reagent. Catalytic variant, involving treatment with excess of periodic acid (H5IO6) have been described.[14]

Two-step oxidation of alcohols to acids via isolated aldehydes

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As a lot of the aforementioned conditions for the oxidations of primary alcohols to acids are harsh and not compatible with common protection groups, organic chemists often use a two-step procedure for the oxidation to acids. The alcohol is oxidized to an aldehyde using one of the many procedures above. This sequence is often used in natural product synthesis as in their synthesis of platencin.[16]

Niche methods and reagents

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Ruthenium tetroxide is an aggressive, seldom-used agent that allows mild reaction conditions.

Heyns oxidation.[17]

The use of chlorites as terminal oxidants in conjunction with both hypochlorites and TEMPO gives carboxylic acids without chlorination side products.[18] The reaction is usually carried out in two steps in the same pot: partial oxidation is effected with TEMPO and hypochlorite, then chlorite is added to complete the oxidation. Only primary alcohol oxidation is observed. In conjunction with Sharpless dihydroxylation, this method can be used to generate enantiopure α-hydroxy acids.[19]

The Pinnick oxidation uses sodium chlorite.[20]

References

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1. ^ Burton, George et al. (2000). Salters Advanced Chemistry: Chemical (2nd ed.). Heinemann. ISBN 0-435-63120-9
2. ^ a b c d Teles, J. Henrique; Hermans, Ive; Franz, Gerhard; Sheldon, Roger A. (2015). "Oxidation". Ullmann's Encyclopedia of Industrial Chemistry. pp. 1–103. doi:10.1002/14356007.a18_261.pub2. ISBN 978-3-527-30385-4.
3. ^ "Chromium-based Reagents". Oxidation of Alcohols to Aldehydes and Ketones. Basic Reactions in Organic Synthesis. 2006. pp. 1–95. doi:10.1007/0-387-25725-X_1. ISBN 0-387-23607-4.
4. ^ J. C. Collins, W.W. Hess (1972). "Aldehydes from Primary Alcohols by Oxidation with Chromium Trioxide: Heptanal". Organic Syntheses. 52: 5. doi:10.15227/orgsyn.052.0005.
5. ^ Dess, D. B.; Martin, J. C. J. Am. Chem. Soc. 1991, 113, 7277–87.
6. ^ J. S. Yadav, et al. "Recyclable 2nd generation ionic liquids as green solvents for the oxidation of alcohols with hypervalent iodine reagents", Tetrahedron, 2004, 60, 2131–35
7. ^ Stevens R, Chapman KT, Weller HN (1980). "Convenient and inexpensive procedure for oxidation of secondary alcohols to ketones". Journal of Organic Chemistry. 45 (10): 2030–2032. doi:10.1021/jo01298a066.
8. ^ Parmeggiani, Camilla; Cardona, Francesca (2012-01-03). "Transition metal based catalysts in the aerobic oxidation of alcohols". Green Chemistry. 14 (3): 547–564. doi:10.1039/C2GC16344F. ISSN 1463-9270.
9. ^ Nicolaou KC, Adsool VA, Hale CR (April 2010). "An expedient procedure for the oxidative cleavage of olefinic bonds with PhI(OAc)2, NMO, and catalytic OsO4". Organic Letters. 12 (7): 1552–5. doi:10.1021/ol100290a. PMC 2848477. PMID 20192259.
10. ^ Fournier, H.M. (1907). "Transformation des alcools primaires saturès en acides monobasiques correspondants". C. R. Acad. Sci.: 331.
11. ^ Fournier, H.M. (20 July 1909). "Sur la préparation des acides gras et de leurs anhydres". Bull. Soc. Chim. Fr.: 920.
12. ^ Ciufolini, M.A.; Swaminathan, S. (1989). "Synthesis of a model depsipeptide segment of Luzopeptins (BBM 928), potent antitumor and antiretroviral antibiotics". Tetrahedron Lett. 30 (23): 3027. doi:10.1016/S0040-4039(00)99393-6.
13. ^ "Chromium-based Reagents". Oxidation of Alcohols to Aldehydes and Ketones. Basic Reactions in Organic Synthesis. 2006. pp. 1–95. doi:10.1007/0-387-25725-X_1. ISBN 0-387-23607-4.
14. ^ Song, Z.J.; Zhao, M.; Desmond, R.; Devine, P.; Tschaen, D.M.; Tillyer, R.; Frey, L.; Heid, R.; Xu, F.; Foster, B.; Li, J.; Reamer, R.; Volante, R.; Grabowski, E.J.J.; Dolling, U.H.; Reider, P.J. (1999). "Practical Asymmetric Synthesis of an Endothelin Receptor Antagonist". J. Org. Chem. 64 (26): 9658. doi:10.1021/jo991292t.
15. ^ Crimmins, M.T. & DeBaillie, A.C. (2006). "Enantioselective Total Synthesis of Bistramide A". J. Am. Chem. Soc. 128 (15): 4936–7. doi:10.1021/ja057686l. PMC 2546575. PMID 16608311.
16. ^ Nicolaou K.C.; Scott Tria G.; Edmonds D. J. (2008). "Total Synthesis of Platencin". Angew. Chem. 120 (9): 1804. doi:10.1002/ange.200800066.
17. ^ Marcos Fernández; Gabriel Tojo (2006). Oxidation of Primary Alcohols to Carboxylic Acids: A Guide to Current Common Practice (Basic Reactions in Organic Synthesis). Berlin: Springer. ISBN 0-387-35431-X.
18. ^ Song, Z. J.; Zhao, M.; Desmond, R.; Devine, P.; Tschaen, D. M.; Tillyer, R.; Frey, L.; Heid, R.; Xu, F.; Foster, B.; Li, J.; Reamer, R.; Volante, R.; Grabowski, E. J. J.; Dolling, U. H.; Reider, P. J.; Okada, S.; Kato, Y.; Mano, E. J. Org. Chem. 1999, 64, 9658.
19. ^ Sharpless, K. B.; Amberg, W.; Bennani, Y. L.; Crispino, G. A.; Hartung, J.; Jeong, K. S.; Kwong, H. L.; Morikawa, K.; Wang, Z. M.; Xu, D.; Zhang, X. L. J. Org. Chem. 1992, 57, 2768.
20. ^ Bal B.S.; Childers, Jr. W.E.; Pinnick H.W. (1981). "Oxidation of α,β-unsaturated aldehydes". Tetrahedron (abstract). 37 (11): 2091. doi:10.1016/S0040-4020(01)97963-3.

v t e Alcohols
By consumption	Alcohols found inalcoholic drinks 1-Propanol 2-Methyl-1-butanol Ethanol Isoamyl alcohol Isobutanol Phenethyl alcohol tert-Amyl alcohol tert-Butyl alcohol Tryptophol Medical alcohol Ethchlorvynol Methylpentynol Methanol poisoning Ethanol Toxic alcohols Isopropyl alcohol Methanol
Primaryalcohols (1°)	Methanol 4-Methylcyclohexanemethanol Aminomethanol Cyclohexylmethanol Methoxymethanol Methylazoxymethanol Trifluoromethanol Ethanol 1-Aminoethanol 2,2,2-Trichloroethanol 2,2,2-Trifluoroethanol 2-(2-Ethoxyethoxy)ethanol 2-(2-Methoxyethoxy)ethanol 2-(2-Methoxyethoxy)ethanol 2-Butoxyethanol 2-Chloroethanol 2-Ethoxyethanol 2-Fluoroethanol 2-Mercaptoethanol 2-Methoxyethanol Aminoethylethanolamine Diethylethanolamine Dimethylethanolamine Ethanol Ethanolamine N,N-Diisopropylaminoethanol N-Methylethanolamine Phenoxyethanol Tribromoethanol Butanol 2-Methyl-1-butanol Isobutanol n-Butanol Straight-chainsaturatedC1 — C9 Methanol Ethanol 1-Propanol 1-Butanol 1-Pentanol 1-Hexanol 1-Heptanol 1-Octanol (capryl) 1-Nonanol (pelargonic) Straight-chainsaturatedC10 — C19 1-Decanol (capric) 1-Undecanol (hendecyl) 1-Dodecanol (lauryl) 1-Tridecanol 1-Tetradecanol (myristyl) 1-Pentadecanol 1-Hexadecanol (cetyl / palmityl) 1-Heptadecanol 1-Octadecanol (stearyl) 1-Nonadecanol Straight-chainsaturatedC20 — C29 1-Icosanol (arachidyl) 1-Heneicosanol 1-Docosanol (behenyl) 1-Tricosanol 1-Tetracosanol (lignoceryl) 1-Pentacosanol 1-Hexacosanol (ceryl) 1-Heptacosanol 1-Octacosanol (cluytyl / montanyl) 1-Nonacosanol Straight-chainsaturatedC30 — C39 1-Triacontanol (melissyl / myricyl) 1-Hentriacontanol 1-Dotriacontanol (lacceryl) 1-Tritriacontanol 1-Tetratriacontanol (geddyl) 1-Pentatriacontanol 1-Hexatriacontanol 1-Heptatriacontanol 1-Octatriacontanol 1-Nonatriacontanol Straight-chainsaturatedC40 — C49 1-Tetracontanol 1-Hentetracontanol 1-Dotetracontanol 1-Tritetracontanol 1-Tetratetracontanol 1-Pentatetracontanol 1-Hexatetracontanol 1-Heptatetracontanol 1-Octatetracontanol 1-Nonatetracontanol 2-Ethylhexanol Allyl alcohol Anisyl alcohol Benzyl alcohol Cinnamyl alcohol Crotyl alcohol Furfuryl alcohol Isoamyl alcohol Neopentyl alcohol Nicotinyl alcohol Perillyl alcohol Phenethyl alcohol Prenol Propargyl alcohol Salicyl alcohol Tryptophol Vanillyl alcohol Veratrole alcohol
Secondary alcohols (2°)	1-Phenylethanol 2-Butanol 2-Deoxyerythritol 2-Heptanol 3-Heptanol 2-Hexanol 3-Hexanol 3-Methyl-2-butanol 2-Nonanol 2-Octanol 2-Pentanol 3-Pentanol Cyclohexanol Cyclopentanol Cyclopropanol Diphenylmethanol Isopropanol Pinacolyl alcohol Pirkle's alcohol Propylene glycol methyl ether
Tertiary alcohols (3°)	2-Methyl-2-pentanol 2-Methylheptan-2-ol 2-Methylhexan-2-ol 3-Methyl-3-pentanol 3-Methyloctan-3-ol Diacetone alcohol Ethchlorvynol Methylpentynol Nonafluoro-tert-butyl alcohol tert-Amyl alcohol tert-Butyl alcohol Triphenylethanol Triphenylmethanol
Hydric alcohols	Monohydric alcohols Methanol (C1) Ethanol (C2) Isopropanol (C3) 1-Butanol (C4) 1-Pentanol (C5) Cetyl alcohol (C16) Dihydric alcohols Ethylene glycol Propylene glycol Trihydric alcohols Glycerol Polyhydric alcohols (sugar alcohols) Pentaerythritol Ethylene glycol (C2) Glycerol, Propylene glycol (C3) Erythritol, Threitol (C4) Xylitol (C5) Mannitol, Sorbitol (C6) Volemitol (C7)
Amyl alcohols	2,2-Dimethylpropan-1-ol 2-Methylbutan-1-ol 2-Methylbutan-2-ol 3-Methylbutan-1-ol 3-Methylbutan-2-ol Pentan-1-ol Pentan-2-ol Pentan-3-ol
Aromatic alcohols	Benzyl alcohol 2,4-Dichlorobenzyl alcohol 3-Nitrobenzyl alcohol
Saturatedfatty alcohols	Cetostearyl alcohol Decanol Lauryl alcohol Myristyl alcohol Nonanol Octanol Tridecanol Undecanol
Branched andunsaturatedfatty alcohols	3-Methyl-3-pentanol Erucyl alcohol Linolenyl alcohol Linoleyl alcohol Oleyl alcohol Palmitoleyl alcohol tert-Amyl alcohol tert-Butyl alcohol
Sugar alcohols	C1 — C7 Methylene glycol (C1) Ethylene glycol (C2) Glycerol (C3) Erythritol (C4) Threitol (C4) Arabitol (C5) Ribitol (C5) Xylitol (C5) Mannitol (C6) Sorbitol (C6) Galactitol (C6) Iditol (C6) Volemitol (C7) Deoxy sugar alcohols Fucitol Cyclic sugar alcohols Inositol Glycylglycitols Maltitol Lactitol Isomalt Maltotriitol Maltotetraitol Polyglycitol
Terpene alcohols	Monoterpene alcohols Borneol Citronellol Geraniol Linalool Menthol Nerol Rhodinol Terpineol Sesquiterpene alcohols Bisabolol Farnesol Nerolidol Patchoulol Diterpene alcohols Phytol
Dialcohols	1,4-Butanediol 1,5-Pentanediol 2-Methyl-2-propyl-1,3-propanediol Diethylpropanediol Ethylene glycol
Trialcohols	Glycerol
Sterols	Cholesterol Ergosterol Lanosterol β-Sitosterol Stigmasterol
Fluoroalcohols	1,3-Difluoro-2-propanol 2,2,2-Trifluoroethanol 2-Fluoroethanol Nonafluoro-tert-butyl alcohol Trifluoromethanol
Preparations	Substitution of haloalkane Carbonyl reduction Ether cleavage Hydrolysis of epoxide Hydration of alkene Ziegler process
Reactions	Deprotonation Protonation Alcohol oxidation Glycol cleavage Nucleophilic substitution Fischer–Speier esterification Williamson ether synthesis Elimination reaction Nucleophilic substitution of carbonyl group Friedel-Crafts alkylation Nucleophilic conjugate addition Transesterification
Category

v t e Topics in organic reactions
Addition reaction Elimination reaction Polymerization Reagents Rearrangement reaction Redox reaction Regioselectivity Stereoselectivity Stereospecificity Substitution reaction
A value Alpha effect Annulene Anomeric effect Antiaromaticity Aromatic ring current Aromaticity Baird's rule Baker–Nathan effect Baldwin's rules Bema Hapothle Beta-silicon effect Bicycloaromaticity Bredt's rule Bürgi–Dunitz angle Catalytic resonance theory Charge remote fragmentation Charge-transfer complex Clar's rule Conformational isomerism Conjugated system Conrotatory and disrotatory Curtin–Hammett principle Dynamic binding (chemistry) Edwards equation Effective molarity Electromeric effect Electron-rich Electron-withdrawing group Electronic effect Electrophile Evelyn effect Flippin–Lodge angle Free-energy relationship Grunwald–Winstein equation Hammett acidity function Hammett equation George S. Hammond Hammond's postulate Homoaromaticity Hückel's rule Hyperconjugation Inductive effect Kinetic isotope effect LFER solvent coefficients (data page) Marcus theory Markovnikov's rule Möbius aromaticity Möbius–Hückel concept More O'Ferrall–Jencks plot Negative hyperconjugation Neighbouring group participation 2-Norbornyl cation Nucleophile Kennedy J. P. Orton Passive binding Phosphaethynolate Polar effect Polyfluorene Ring strain Σ-aromaticity Spherical aromaticity Spiroaromaticity Steric effects Superaromaticity Swain–Lupton equation Taft equation Thorpe–Ingold effect Vinylogy Walsh diagram Woodward–Hoffmann rules Woodward's rules Y-aromaticity Yukawa–Tsuno equation Zaitsev's rule Σ-bishomoaromaticity List of organic reactions Carbon-carbon bond forming reactions Acetoacetic ester synthesis Acyloin condensation Aldol condensation Aldol reaction Alkane metathesis Alkyne metathesis Alkyne trimerisation Alkynylation Allan–Robinson reaction Arndt–Eistert reaction Auwers synthesis Aza-Baylis–Hillman reaction Barbier reaction Barton–Kellogg reaction Baylis–Hillman reaction Benary reaction Bergman cyclization Biginelli reaction Bingel reaction Blaise ketone synthesis Blaise reaction Blanc chloromethylation Bodroux–Chichibabin aldehyde synthesis Bouveault aldehyde synthesis Bucherer–Bergs reaction Buchner ring expansion Cadiot–Chodkiewicz coupling Carbonyl allylation Carbonyl olefin metathesis Castro–Stephens coupling Chan rearrangement Chan–Lam coupling Claisen condensation Claisen rearrangement Claisen-Schmidt condensation Combes quinoline synthesis Corey–Fuchs reaction Corey–House synthesis Coupling reaction Cross-coupling reaction Cross dehydrogenative coupling Cross-coupling partner Dakin–West reaction Darzens reaction Diels–Alder reaction Doebner reaction Wulff–Dötz reaction Ene reaction Enyne metathesis Ethenolysis Favorskii reaction Ferrier carbocyclization Friedel–Crafts reaction Fujimoto–Belleau reaction Fujiwara–Moritani reaction Fukuyama coupling Gabriel–Colman rearrangement Gattermann reaction Glaser coupling Grignard reaction Grignard reagent Hammick reaction Heck reaction Henry reaction Heterogeneous metal catalyzed cross-coupling High dilution principle Hiyama coupling Homologation reaction Horner–Wadsworth–Emmons reaction Hydrocyanation Hydrovinylation Hydroxymethylation Ivanov reaction Johnson–Corey–Chaykovsky reaction Julia olefination Julia–Kocienski olefination Kauffmann olefination Knoevenagel condensation Knorr pyrrole synthesis Kolbe–Schmitt reaction Kowalski ester homologation Kulinkovich reaction Kumada coupling Liebeskind–Srogl coupling Malonic ester synthesis Mannich reaction McMurry reaction Meerwein arylation Methylenation Michael reaction Minisci reaction Mizoroki-Heck vs. Reductive Heck Nef isocyanide reaction Nef synthesis Negishi coupling Nierenstein reaction Nitro-Mannich reaction Nozaki–Hiyama–Kishi reaction Olefin conversion technology Olefin metathesis Palladium–NHC complex Passerini reaction Peterson olefination Pfitzinger reaction Piancatelli rearrangement Pinacol coupling reaction Prins reaction Quelet reaction Ramberg–Bäcklund reaction Rauhut–Currier reaction Reformatsky reaction Reimer–Tiemann reaction Rieche formylation Ring-closing metathesis Robinson annulation Sakurai reaction Seyferth–Gilbert homologation Shapiro reaction Sonogashira coupling Stetter reaction Stille reaction Stollé synthesis Stork enamine alkylation Suzuki reaction Takai olefination Thermal rearrangement of aromatic hydrocarbons Thorpe reaction Ugi reaction Ullmann reaction Wagner-Jauregg reaction Weinreb ketone synthesis Wittig reaction Wurtz reaction Wurtz–Fittig reaction Zincke–Suhl reaction Homologation reactions Arndt–Eistert reaction Hooker reaction Kiliani–Fischer synthesis Kowalski ester homologation Methoxymethylenetriphenylphosphorane Seyferth–Gilbert homologation Wittig reaction Olefination reactions Bamford–Stevens reaction Barton–Kellogg reaction Boord olefin synthesis Chugaev elimination Cope reaction Corey–Winter olefin synthesis Dehydrohalogenation Elimination reaction Grieco elimination Hofmann elimination Horner–Wadsworth–Emmons reaction Hydrazone iodination Julia olefination Julia–Kocienski olefination Kauffmann olefination McMurry reaction Peterson olefination Ramberg–Bäcklund reaction Shapiro reaction Takai olefination Wittig reaction Carbon-heteroatom bond forming reactions Azo coupling Bartoli indole synthesis Boudouard reaction Cadogan–Sundberg indole synthesis Diazonium compound Esterification Grignard reagent Haloform reaction Hegedus indole synthesis Hurd–Mori 1,2,3-thiadiazole synthesis Kharasch–Sosnovsky reaction Knorr pyrrole synthesis Leimgruber–Batcho indole synthesis Mukaiyama hydration Nenitzescu indole synthesis Oxymercuration reaction Reed reaction Schotten–Baumann reaction Ullmann condensation Williamson ether synthesis Yamaguchi esterification Degradation reactions Barbier–Wieland degradation Bergmann degradation Edman degradation Emde degradation Gallagher–Hollander degradation Hofmann rearrangement Hooker reaction Isosaccharinic acid Marker degradation Ruff degradation Strecker degradation Von Braun amide degradation Weerman degradation Wohl degradation Organic redox reactions Acyloin condensation Adkins–Peterson reaction Akabori amino-acid reaction Alcohol oxidation Algar–Flynn–Oyamada reaction Amide reduction Andrussow process Angeli–Rimini reaction Aromatization Autoxidation Baeyer–Villiger oxidation Barton–McCombie deoxygenation Bechamp reduction Benkeser reaction Bergmann degradation Birch reduction Bohn–Schmidt reaction Bosch reaction Bouveault–Blanc reduction Boyland–Sims oxidation Cannizzaro reaction Carbonyl reduction Clemmensen reduction Collins oxidation Corey–Itsuno reduction Corey–Kim oxidation Corey–Winter olefin synthesis Criegee oxidation Dakin oxidation Davis oxidation Deoxygenation Dess–Martin oxidation DNA oxidation Elbs persulfate oxidation Emde degradation Eschweiler–Clarke reaction Étard reaction Fischer–Tropsch process Fleming–Tamao oxidation Fukuyama reduction Ganem oxidation Glycol cleavage Griesbaum coozonolysis Grundmann aldehyde synthesis Haloform reaction Hydrogenation Hydrogenolysis Hydroxylation Jones oxidation Kiliani–Fischer synthesis Kolbe electrolysis Kornblum oxidation Kornblum–DeLaMare rearrangement Leuckart reaction Ley oxidation Lindgren oxidation Lipid peroxidation Lombardo methylenation Luche reduction Markó–Lam deoxygenation McFadyen–Stevens reaction Meerwein–Ponndorf–Verley reduction Methionine sulfoxide Miyaura borylation Mozingo reduction Noyori asymmetric hydrogenation Omega oxidation Oppenauer oxidation Oxygen rebound mechanism Ozonolysis Parikh–Doering oxidation Pinnick oxidation Prévost reaction Reduction of nitro compounds Reductive amination Riley oxidation Rosenmund reduction Rubottom oxidation Sabatier reaction Sarett oxidation Selenoxide elimination Shapiro reaction Sharpless asymmetric dihydroxylation Epoxidation of allylic alcohols Sharpless epoxidation Sharpless oxyamination Stahl oxidation Staudinger reaction Stephen aldehyde synthesis Swern oxidation Transfer hydrogenation Wacker process Wharton reaction Whiting reaction Wohl–Aue reaction Wolff–Kishner reduction Wolffenstein–Böters reaction Zinin reaction Rearrangement reactions 1,2-rearrangement 1,2-Wittig rearrangement 2,3-sigmatropic rearrangement 2,3-Wittig rearrangement Achmatowicz reaction Alkyne zipper reaction Allen–Millar–Trippett rearrangement Allylic rearrangement Alpha-ketol rearrangement Amadori rearrangement Arndt–Eistert reaction Aza-Cope rearrangement Baker–Venkataraman rearrangement Bamberger rearrangement Banert cascade Beckmann rearrangement Benzilic acid rearrangement Bergman cyclization Bergmann degradation Boekelheide reaction Brook rearrangement Buchner ring expansion Carroll rearrangement Chan rearrangement Claisen rearrangement Cope rearrangement Corey–Fuchs reaction Cornforth rearrangement Criegee rearrangement Curtius rearrangement Demjanov rearrangement Di-π-methane rearrangement Dimroth rearrangement Divinylcyclopropane-cycloheptadiene rearrangement Dowd–Beckwith ring-expansion reaction Electrocyclic reaction Ene reaction Enyne metathesis Favorskii reaction Favorskii rearrangement Ferrier carbocyclization Ferrier rearrangement Fischer–Hepp rearrangement Fries rearrangement Fritsch–Buttenberg–Wiechell rearrangement Gabriel–Colman rearrangement Group transfer reaction Halogen dance rearrangement Hayashi rearrangement Hofmann rearrangement Hofmann–Martius rearrangement Ireland–Claisen rearrangement Jacobsen rearrangement Kornblum–DeLaMare rearrangement Kowalski ester homologation Lobry de Bruyn–Van Ekenstein transformation Lossen rearrangement McFadyen–Stevens reaction McLafferty rearrangement Meyer–Schuster rearrangement Mislow–Evans rearrangement Mumm rearrangement Myers allene synthesis Nazarov cyclization reaction Neber rearrangement Newman–Kwart rearrangement Overman rearrangement Oxy-Cope rearrangement Pericyclic reaction Piancatelli rearrangement Pinacol rearrangement Pummerer rearrangement Ramberg–Bäcklund reaction Ring expansion and contraction Ring-closing metathesis Rupe reaction Schmidt reaction Semipinacol rearrangement Seyferth–Gilbert homologation Sigmatropic reaction Skattebøl rearrangement Smiles rearrangement Sommelet–Hauser rearrangement Stevens rearrangement Stieglitz rearrangement Thermal rearrangement of aromatic hydrocarbons Tiffeneau–Demjanov rearrangement Vinylcyclopropane rearrangement Wagner–Meerwein rearrangement Wallach rearrangement Weerman degradation Westphalen–Lettré rearrangement Willgerodt rearrangement Wolff rearrangement Ring forming reactions 1,3-Dipolar cycloaddition Annulation Azide-alkyne Huisgen cycloaddition Baeyer–Emmerling indole synthesis Bartoli indole synthesis Bergman cyclization Biginelli reaction Bischler–Möhlau indole synthesis Bischler–Napieralski reaction Blum–Ittah aziridine synthesis Bobbitt reaction Bohlmann–Rahtz pyridine synthesis Borsche–Drechsel cyclization Bucherer carbazole synthesis Bucherer–Bergs reaction Cadogan–Sundberg indole synthesis Camps quinoline synthesis Chichibabin pyridine synthesis Cook–Heilbron thiazole synthesis Cycloaddition Darzens reaction Davis–Beirut reaction De Kimpe aziridine synthesis Debus–Radziszewski imidazole synthesis Dieckmann condensation Diels–Alder reaction Feist–Benary synthesis Ferrario–Ackermann reaction Fiesselmann thiophene synthesis Fischer indole synthesis Fischer oxazole synthesis Friedländer synthesis Gewald reaction Graham reaction Hantzsch pyridine synthesis Hegedus indole synthesis Hemetsberger indole synthesis Hofmann–Löffler reaction Hurd–Mori 1,2,3-thiadiazole synthesis Iodolactonization Isay reaction Jacobsen epoxidation Johnson–Corey–Chaykovsky reaction Knorr pyrrole synthesis Knorr quinoline synthesis Kröhnke pyridine synthesis Kulinkovich reaction Larock indole synthesis Madelung synthesis Nazarov cyclization reaction Nenitzescu indole synthesis Niementowski quinazoline synthesis Niementowski quinoline synthesis Paal–Knorr synthesis Paternò–Büchi reaction Pechmann condensation Petrenko-Kritschenko piperidone synthesis Pictet–Spengler reaction Pomeranz–Fritsch reaction Prilezhaev reaction Pschorr cyclization Reissert indole synthesis Ring-closing metathesis Robinson annulation Sharpless epoxidation Simmons–Smith reaction Skraup reaction Urech hydantoin synthesis Van Leusen reaction Wenker synthesis Cycloaddition 1,3-Dipolar cycloaddition 4+4 Photocycloaddition (4+3) cycloaddition 6+4 Cycloaddition Alkyne trimerisation Aza-Diels–Alder reaction Azide-alkyne Huisgen cycloaddition Bradsher cycloaddition Cheletropic reaction Conia-ene reaction Cyclopropanation Diazoalkane 1,3-dipolar cycloaddition Diels–Alder reaction Enone–alkene cycloadditions Hexadehydro Diels–Alder reaction Intramolecular Diels–Alder cycloaddition Inverse electron-demand Diels–Alder reaction Ketene cycloaddition McCormack reaction Metal-centered cycloaddition reactions Nitrone-olefin (3+2) cycloaddition Oxo-Diels–Alder reaction Ozonolysis Pauson–Khand reaction Povarov reaction Prato reaction Retro-Diels–Alder reaction Staudinger synthesis Trimethylenemethane cycloaddition Vinylcyclopropane (5+2) cycloaddition Wagner-Jauregg reaction Heterocycle forming reactions Algar–Flynn–Oyamada reaction Allan–Robinson reaction Auwers synthesis Bamberger triazine synthesis Banert cascade Barton–Zard reaction Bernthsen acridine synthesis Bischler–Napieralski reaction Bobbitt reaction Boger pyridine synthesis Borsche–Drechsel cyclization Bucherer carbazole synthesis Bucherer–Bergs reaction Chichibabin pyridine synthesis Cook–Heilbron thiazole synthesis Diazoalkane 1,3-dipolar cycloaddition Einhorn–Brunner reaction Erlenmeyer–Plöchl azlactone and amino-acid synthesis Feist–Benary synthesis Fischer oxazole synthesis Gabriel–Colman rearrangement Gewald reaction Hantzsch ester Hantzsch pyridine synthesis Herz reaction Knorr pyrrole synthesis Kröhnke pyridine synthesis Lectka enantioselective beta-lactam synthesis Lehmstedt–Tanasescu reaction Niementowski quinazoline synthesis Nitrone-olefin (3+2) cycloaddition Paal–Knorr synthesis Pellizzari reaction Pictet–Spengler reaction Pomeranz–Fritsch reaction Prilezhaev reaction Robinson–Gabriel synthesis Stollé synthesis Urech hydantoin synthesis Wenker synthesis Wohl–Aue reaction