Elimination reaction
In cases where the molecule is able to stabilize an anion but possesses a poor leaving group, a third type of reaction, E1CB, exists.In general, with the exception of reactions in which E2 is impossible because β hydrogens are unavailable (e.g. methyl, allyl, and benzyl halides),[4] clean SN2 substitution is hard to achieve when strong bases are used, as alkene products arising from elimination are almost always observed to some degree.[5] In one study[6] the kinetic isotope effect (KIE) was determined for the gas phase reaction of several alkyl halides with the chlorate ion.The ability to form a stable product containing a C=C or C=X bond, as well as orbital alignment considerations, strongly favors β-elimination over other elimination processes.For instance, α-elimination the elements of HCl from chloroform (CHCl3) in the presence of strong base is a classic approach for the generation of dichlorocarbene, :CCl2, as a reactive intermediate.(Confusingly, in organometallic terminology, the terms α-elimination and α-abstraction refer to processes that result in formation of a metal-carbene complex.In certain special cases, γ- and higher eliminations to form three-membered or larger rings is also possible in both organic and organometallic processes.
cyclohexanolcyclohexenesulfuric acidorganic reactionsubstituentsleaving grouppyrolysisxanthateacetateestersEi mechanismPi bondtransition statereaction ratesecond orderhalogenantiperiplanarstaggered conformationsynperiplanareclipsedhybridizationrate determining stepdeuterium isotope effectSN2 reactionisobutylbromidepotassium ethoxideethanolisobutenepotassium bromideIonizationcarbocationdeprotonationtertiaryrate-determining stepSN1 reactionssulfonate estermentholrearrangement reactionshalogensiodidebromidenucleophilic substitutionsteric hindrancetemperatureentropynucleophilepotassium tert-butoxideWilliamson ether synthesiskinetic isotope effectchloratet-butyl chloridemethyl chloridecarbon monoxideisocyanidesdichlorocarbenereductive eliminationChristopher Kelk IngoldE1cB-elimination reactionOrganic SynthesesMarch, JerryJournal of Chemical EducationBibcodeJ. Am. Chem. Soc.reaction mechanismsNucleophilic substitutionsUnimolecular nucleophilic substitutionBimolecular nucleophilic substitutionNucleophilic aromatic substitutionNucleophilic internal substitutionNucleophilic acyl substitutionElectrophilic substitutionsElectrophilic aromatic substitutionUnimolecular eliminationE1cB-eliminationBimolecular eliminationEi eliminationAddition reactionsElectrophilic additionNucleophilic additionFree-radical additionCycloadditionOxidative additionIntramolecular reactionIsomerizationPhotodissociationLindemann–Hinshelwood mechanismRRKM theoryElectron/Proton transferHarpoon reactionGrotthuss mechanismMarcus theoryInner sphere electron transferOuter sphere electron transferSolvent effectsCage effectMatrix isolationElementary reactionReaction dynamicsReactive intermediateRadical (chemistry)MolecularityStereochemistryCatalysisCollision theoryArrow pushingPotential energy surfaceMore O'Ferrall–Jencks plotChemical kineticsRate equationEquilibrium constantReaction coordinateEnergy profile (chemistry)Transition state theoryActivation energyActivated complexArrhenius equationEyring equationMichaelis–Menten kineticsDiffusion-controlled reactionorganic reactionsAddition reactionPolymerizationRearrangement reactionRedox reactionRegioselectivityStereoselectivity