Organic Reactions — Carbon Chemistry in Action
40 reacciones
Organic reactions involve compounds based on carbon skeletons — the chemistry of life. With carbon's ability to form four covalent bonds and create stable chains, rings, and branched structures, organic chemistry encompasses millions of known compounds. Organic reactions include substitution, addition, elimination, rearrangement, and polymerization, each following distinct mechanistic pathways governed by electronic and steric effects.
Mecanismo de reacción
Organic reaction mechanisms describe the step-by-step bond-breaking and bond-forming process. Nucleophilic substitution (SN1, SN2) involves a nucleophile replacing a leaving group. Electrophilic addition to alkenes follows Markovnikov's rule — the electrophile adds to the less substituted carbon. Elimination reactions (E1, E2) remove atoms to form double bonds, following Zaitsev's rule for the most substituted product. Understanding these mechanisms allows chemists to predict products, optimize yields, and design synthetic routes to complex molecules.
Ejemplos cotidianos
Fermentation is an organic reaction where yeast enzymes convert glucose into ethanol and CO2 — the basis of beer, wine, and bread. Soap-making (saponification) is base-catalyzed hydrolysis of fats into glycerol and fatty acid salts. Aspirin synthesis is an esterification reaction between salicylic acid and acetic anhydride, one of the most widely taught organic reactions in undergraduate chemistry.
Importancia industrial
The pharmaceutical industry is built on organic reactions — total synthesis of complex drug molecules can involve 20-40 reaction steps. Polymerization reactions produce plastics (polyethylene, PET, nylon) totaling over 400 million tonnes annually. The petrochemical industry converts crude oil fractions into thousands of organic chemicals through cracking, reforming, and functional group transformations.
Safety Note
Many organic solvents are flammable and toxic. Work in well-ventilated areas or fume hoods. Organic peroxides are shock-sensitive explosives — never distill ethers without first testing for peroxide formation. Carcinogenic reagents (benzene, certain aromatic amines) require strict exposure controls.
Acoplamiento de Suzuki
ArBr + ArB(OH)₂ → Ar–Ar + B(OH)₃ + HBr
The Suzuki reaction couples an aryl halide with an aryl boronic acid using a palladium catalyst to form a biaryl …
Adición de Michael
CH₂(COOC₂H₅)₂ + CH₂=CHCOCH₃ → product
A Michael donor (stabilized carbanion) adds to the beta-carbon of a Michael acceptor (alpha,beta-unsaturated carbonyl). This 1,4-conjugate addition forms a …
Adición electrófila de HBr al etileno
C₂H₄ + HBr → C₂H₅Br
Ethylene undergoes electrophilic addition with hydrogen bromide to form bromoethane. The pi electrons of the C=C double bond attack the …
Alquilación de Friedel-Crafts de benceno
C₆H₆ + CH₃Cl → C₆H₅CH₃ + HCl
Benzene reacts with chloromethane in the presence of aluminum chloride catalyst to form toluene and HCl. AlCl₃ generates the electrophilic …
Aminación de Buchwald-Hartwig
ArBr + R₂NH → ArNR₂ + HBr
The Buchwald-Hartwig reaction couples aryl halides with amines using a palladium catalyst to form aryl C-N bonds. This transformation, developed …
Bromación de etileno
C₂H₄ + Br₂ → C₂H₄Br₂
Ethylene reacts with bromine in an electrophilic addition reaction to form 1,2-dibromoethane. The brown color of bromine water is decolorized …
Condensación aldólica de acetaldehído
2CH₃CHO → CH₃CH(OH)CH₂CHO
Two molecules of acetaldehyde combine in a base-catalyzed aldol reaction to form 3-hydroxybutanal (aldol). The alpha-hydrogen of one molecule is …
Condensación de Claisen (acetato de etilo)
2CH₃COOC₂H₅ → CH₃COCH₂COOC₂H₅ + C₂H₅OH
Two molecules of ethyl acetate undergo base-catalyzed condensation to form ethyl acetoacetate (a beta-keto ester) and ethanol. The enolate of …
Deshidratación de etanol
C₂H₅OH → C₂H₄ + H₂O
Ethanol is dehydrated to ethylene by concentrated sulfuric acid at 170 C or by passing over heated alumina. This elimination …
Electrólisis de Kolbe
2CH₃COO⁻ → C₂H₆ + 2CO₂ + 2e⁻
Kolbe electrolysis oxidizes carboxylate anions at the anode, decarboxylating them to form alkyl radicals that dimerize. Two acetate ions lose …
Eliminación de Hofmann
R₃N(CH₃)⁺ + OH⁻ → alkene + R₃N + H₂O
The Hofmann elimination converts a quaternary ammonium salt to an alkene, amine, and water upon heating with base. Unlike E2 …
Eliminación E2 (deshidrohalogenación)
C₂H₅Br + KOH → C₂H₄ + KBr + H₂O
Strong base (KOH in ethanol) removes a beta-hydrogen and the halide leaves simultaneously in a concerted E2 elimination to form …
Epoxidación de alquenos (mCPBA)
R₂C=CR₂ + mCPBA → epoxide + mCBA
Meta-chloroperoxybenzoic acid (mCPBA) converts alkenes to epoxides (oxiranes) in a concerted syn-addition. The peracid oxygen inserts into the C=C bond, …
Esterificación de Fischer (etanol + ácido acético)
CH₃COOH + C₂H₅OH ⇌ CH₃COOC₂H₅ + H₂O
Acetic acid reacts with ethanol in the presence of an acid catalyst to form ethyl acetate and water. This reversible …
Formación de amida (ácido acético + amoniaco)
CH₃COOH + NH₃ → CH₃CONH₂ + H₂O
Acetic acid reacts with ammonia to first form ammonium acetate, which upon strong heating loses water to form acetamide. The …
Halogenación de metano (cloración)
CH₄ + Cl₂ → CH₃Cl + HCl
Methane undergoes free radical substitution with chlorine in the presence of UV light or heat. The mechanism involves initiation (Cl₂ …
Hidratación de etileno
C₂H₄ + H₂O → C₂H₅OH
Ethylene undergoes acid-catalyzed hydration to form ethanol. This is the primary industrial method for producing synthetic ethanol, using phosphoric acid …
Hidrogenación catalítica de etileno
C₂H₄ + H₂ → C₂H₆
Ethylene is reduced to ethane by addition of hydrogen across the double bond, catalyzed by a transition metal surface. Both …
Metátesis de olefinas
2 R–CH=CH–R' ⇌ R–CH=CH–R + R'–CH=CH–R'
Olefin metathesis exchanges substituents around carbon-carbon double bonds using a ruthenium or molybdenum carbene catalyst. The mechanism involves [2+2] cycloaddition …
Nitración de benceno
C₆H₆ + HNO₃ → C₆H₅NO₂ + H₂O
Benzene undergoes electrophilic aromatic substitution with nitric acid in the presence of sulfuric acid to form nitrobenzene. The active electrophile …
Oxidación de Baeyer-Villiger
R₂CO + RCO₃H → R₂CO₂ (ester or lactone)
A peracid oxidizes a ketone by inserting an oxygen atom between the carbonyl carbon and an adjacent carbon, converting the …
Oxidación de Swern
RCH₂OH + (COCl)₂ + DMSO → RCHO + DMS + CO₂ + CO + 2HCl
The Swern oxidation converts primary and secondary alcohols to aldehydes and ketones using DMSO activated by oxalyl chloride, followed by …
Oxidación de un alcohol primario a aldehído
RCH₂OH + [O] → RCHO + H₂O
Primary alcohols are oxidized to aldehydes using mild oxidizing agents like PCC or Dess-Martin periodinane. Stronger oxidants (KMnO₄, CrO₃) would …
Oxidación de un alcohol secundario a cetona
R₂CHOH + [O] → R₂CO + H₂O
Secondary alcohols are oxidized to ketones by various oxidizing agents. Unlike primary alcohols, secondary alcohols cannot be over-oxidized because ketones …
Ozonólisis de alquenos
R₂C=CR₂ + O₃ → R₂C=O + R₂C=O
Ozone cleaves carbon-carbon double bonds to form carbonyl compounds (aldehydes and/or ketones). The reaction proceeds through a molozonide intermediate that …
Polimerización del cloruro de vinilo a PVC
nCH₂=CHCl → (–CH₂–CHCl–)ₙ
Vinyl chloride monomer (VCM) undergoes free radical addition polymerization to form polyvinyl chloride (PVC), the third most produced plastic worldwide. …
Polimerización del estireno a poliestireno
nC₈H₈ → (–CH₂–CH(C₆H₅)–)ₙ
Styrene undergoes free radical addition polymerization to form polystyrene. The vinyl group polymerizes while the pendant phenyl groups provide rigidity …
Polimerización del etileno a polietileno
nC₂H₄ → (–CH₂–CH₂–)ₙ
Ethylene molecules undergo addition polymerization to form polyethylene, the world's most produced plastic. The C=C double bond opens and links …
Polimerización por condensación (nylon 6,6)
nH₂N(CH₂)₆NH₂ + nHOOC(CH₂)₄COOH → nylon 6,6 + nH₂O
Hexamethylenediamine reacts with adipic acid to form nylon 6,6 through condensation polymerization, releasing water. Each amide bond formed links the …
Reacción de Cannizzaro de formaldehído
2HCHO + NaOH → HCOONa + CH₃OH
In the Cannizzaro reaction, two molecules of a non-enolizable aldehyde undergo disproportionation in the presence of strong base. One molecule …
Reacción de Diels-Alder (butadieno + etileno)
C₄H₆ + C₂H₄ → C₆H₁₀
A conjugated diene (1,3-butadiene) reacts with a dienophile (ethylene) in a [4+2] cycloaddition to form cyclohexene. This pericyclic reaction proceeds …
Reacción de Grignard con formaldehído
CH₃MgBr + HCHO → CH₃CH₂OH (after hydrolysis)
A Grignard reagent (methylmagnesium bromide) adds to formaldehyde, and after aqueous workup produces a primary alcohol. Grignard reagents are organomagnesium …
Reacción de Heck (acoplamiento catalizado por paladio)
ArX + CH₂=CHR → ArCH=CHR + HX
The Heck reaction couples an aryl or vinyl halide with an alkene using a palladium catalyst and base. The mechanism …
Reacción de Wittig
Ph₃P=CHR + R'CHO → R'CH=CHR + Ph₃P=O
A phosphorus ylide (Wittig reagent) reacts with an aldehyde or ketone to form an alkene and triphenylphosphine oxide. This reaction …
Reacción SN2 (bromuro de etilo + hidróxido)
C₂H₅Br + OH⁻ → C₂H₅OH + Br⁻
Hydroxide ion attacks the carbon bearing bromine in a backside attack, simultaneously displacing bromide. This bimolecular nucleophilic substitution (SN2) proceeds …
Saponificación (grasa + NaOH)
fat + 3NaOH → glycerol + 3 sodium carboxylate (soap)
Saponification is the base-catalyzed hydrolysis of triglyceride fats or oils by sodium hydroxide to produce glycerol and sodium salts of …
Síntesis de éteres de Williamson
C₂H₅ONa + CH₃I → C₂H₅OCH₃ + NaI
Sodium ethoxide (an alkoxide) reacts with methyl iodide in an SN2 reaction to form ethyl methyl ether. This is the …
Transesterificación (producción de biodiésel)
triglyceride + 3CH₃OH → 3 FAME + glycerol
Triglyceride fats react with methanol in the presence of a base catalyst to produce fatty acid methyl esters (FAME, biodiesel) …
Transposición de Beckmann (oxima de ciclohexanona)
cyclohexanone oxime → caprolactam
Cyclohexanone oxime undergoes acid-catalyzed Beckmann rearrangement to form caprolactam, expanding the six-membered ring to a seven-membered lactam. The anti group …
Transposición de Cope
1,5-hexadiene ⇌ 1,5-hexadiene (rearranged)
The Cope rearrangement is a [3,3]-sigmatropic rearrangement of 1,5-dienes that proceeds through a chair-like transition state. No bonds are broken …