Organic Chemistry Terms Starting with E
Definitions of 45 organic chemistry terms that start with E, such as β-Elimination, E, E1. Plain-language explanations linked to reactions and reagents.
Terms starting with E
- β-Elimination: Removes groups from neighboring α/β carbons to form a double bond.
- E: In alkene stereochemistry, high-priority groups are on opposite sides. Think entgegen = opposite.
- E1: Two-step elimination through a carbocation intermediate.
- E1cb Mechanism: Elimination where a base first forms a carbanion/enolate-like intermediate before the leaving group leaves.
- E2: One-step elimination where a base removes H while the leaving group leaves.
- Eclipsed Conformation: Bonds line up behind each other in a Newman projection; usually higher energy.
- Edman Degradation: Method for identifying amino acids from the N-terminus of a peptide.
- Eicosanoids: Signaling molecules derived from fatty acids.
- Elastomers: Stretchy polymers that can return toward their original shape.
- Electrocyclic Reaction: Pericyclic reaction where a π system forms or opens a ring.
- Electromagnetic Spectrum: Full range of electromagnetic radiation, including UV, visible, IR, and radio waves.
- Electron Density: Where electrons are concentrated in a molecule.
- Electron Impact Ionization (EI): Mass-spec ionization that hits molecules with energetic electrons, often causing fragmentation.
- Electrophile: Electron-pair acceptor. Usually electron-poor.
- Electrophilic Aromatic Substitution: Aromatic H is replaced by an electrophile while aromaticity is ultimately restored.
- Electrophoresis: Separates charged molecules using an electric field.
- Electrospray Ionization (ESI): Gentle MS ionization technique useful for large/polar molecules.
- Electrostatic Potential Map: Colored molecular surface showing electron-rich and electron-poor regions.
- Elimination: Removes groups from neighboring atoms to create a multiple bond.
- Elimination of Radicals: Radical process where bond changes produce elimination products.
- Elimination–Addition: Substitution pathway involving elimination first and addition afterward.
- Enamine: Compound containing C=C–NR₂.
- Enantiomer: One of two non-superimposable mirror-image molecules.
- Enantiomeric Excess (ee): Measures how much one enantiomer dominates over the other.
- Enantiomerically Pure: Sample containing essentially only one enantiomer.
- Enantiotopic: Identical groups where changing one or the other would produce enantiomers.
- Endergonic: Has ΔG > 0; thermodynamically unfavorable in the forward direction.
- Endo: In certain bicyclic reactions, substituents point toward the bridge/interior side.
- Endothermic: Absorbs heat; ΔH > 0.
- Energy of Activation: Energy barrier that reactants must overcome to react.
- Enol: Contains C=C–OH. Often exists in equilibrium with a carbonyl compound.
- Enolate: Resonance-stabilized species formed by removing an α-H next to a carbonyl. Powerful nucleophile.
- Enthalpy: Energy-related thermodynamic quantity often associated with heat changes at constant pressure.
- Entropy: Measure related to how many arrangements/energy distributions are available to a system.
- Enzymes: Biological catalysts.
- Epimer: Diastereomers differing at only one stereocenter.
- Epoxide: Reactive three-membered ring containing oxygen.
- Equatorial Position: Cyclohexane chair position pointing roughly outward around the ring.
- Equilibrium: Forward and reverse reactions occur at equal rates, so overall composition stays constant.
- Estrogens: Family of steroid hormones.
- Ether: Functional group R–O–R′.
- Excited State: Higher-energy electronic state than the ground state.
- Exergonic: Has ΔG < 0; thermodynamically favorable.
- Exo: In certain bicyclic systems, substituent points away from the bridge/interior.
- Exothermic: Releases heat; ΔH < 0.
Open a term starting with E
- β-Elimination
- E
- E1
- E1cb Mechanism
- E2
- Eclipsed Conformation
- Edman Degradation
- Eicosanoids
- Elastomers
- Electrocyclic Reaction
- Electromagnetic Spectrum
- Electron Density
- Electron Impact Ionization (EI)
- Electrophile
- Electrophilic Aromatic Substitution
- Electrophoresis
- Electrospray Ionization (ESI)
- Electrostatic Potential Map
- Elimination
- Elimination of Radicals
- Elimination–Addition
- Enamine
- Enantiomer
- Enantiomeric Excess (ee)
- Enantiomerically Pure
- Enantiotopic
- Endergonic
- Endo
- Endothermic
- Energy of Activation
- Enol
- Enolate
- Enthalpy
- Entropy
- Enzymes
- Epimer
- Epoxide
- Equatorial Position
- Equilibrium
- Estrogens
- Ether
- Excited State
- Exergonic
- Exo
- Exothermic