Organic Chemistry Key Terms – Flashcards

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First Point of Difference Rule
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Rule that states that you number a carbon chain from the side that yields the lowest numbers for substituents
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Cracking
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Cleaving large hydrocarbons to yield smaller ones for petroleum
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Reforming
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Conversion of long aliphatic hydrocarbons to aromatics and branched alkanes, which tend not to knock (preignite)
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Conformers/Rotamers
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Different conformations of the same molecule
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Staggered Conformation
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Conformation in which C-H bonds are arranged such that each one bisects the angle defined by two C-H bonds on an adjacent carbon
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Eclipsed Conformation
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Conformation in which C-H bonds are arranged such that each one is aligned with the C-H bonds on an adjacent carbon
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Anti
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Torsion angle of 180°
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Gauche
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Torsion angle of 60°
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Torsion Angle
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Angle between C-H bonds on adjacent carbons; also known as dihedral angle
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Torsional Strain
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Destabilization associated with eclipsed bonds on adjacent atoms
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Steric Hindrance
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Also known as van der Waals strain; the destabilization of a molecule that results when two of its atoms are too close to each other, like the flagpole hydrogens in cyclohexane's boat conformation
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Angle Strain
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Strain that a molecule experiences because one of more of its bond angles deviate from the ideal value (usually 109.5°)
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Chair Conformation
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Most stable conformation of cyclohexane; nearly free of angle and torsional strain (all bonds are staggered)
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Axial
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Bonds that are parallel to an axis of symmetry that passes through a ring's center
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Equatorial
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Bonds that are located approximately at the center of the molecule of a ring
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1,3-Diaxial Repulsions
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Repulsions between axial substituents on the same side of a ring
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Cyclopentane
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Has planar, envelope, and half-chair conformations
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Spirocyclic Compounds
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Compounds that have one carbon atom common to two different rings
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Substitutive Nomenclature
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Naming that treats alkane chain as the base of the molecule (example: 1-chloropentane; butanone)
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Radicofunctional Nomenclature
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Naming that treats the functional group as the base of the molecule (example: pentylchloride; ethylmethylketone)
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Alkyloxonium
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Conjugate acid of an alcohol of general form ROH₂⁺
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Alkoxide
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Conjugate base of an alcohol of general form RO⁻
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Concerted Reaction
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A reaction that proceeds by way of a single elementary step
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Inductive Effect
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Electron-donating or electron-withdrawing effect of a group that is transmitted by the polarization of electrons in sigma bonds
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Hammond's Postulate
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The statement that if two states, such as a transition state and an intermediate derived from it, are similar in energy, then they are similar in structure
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Regioselectivity
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Reactions in which more than one constitutional/structural isomer can be formed from a single reactant, but in which one isomer predominates
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Vinyl
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Common name for the ethenyl group (CH₂=CH-)
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Allyl
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Common name for the propenyl group (CH₂=CHCH₂-)
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Methylene
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CH₂ group
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Methine
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CH group
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Zusammen
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"Together"; higher priority substituents are on the same side of the double bond
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Entgegen
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"Opposite"; higher priority substituents are on the opposite side of the double bond
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Cahn Ingold Prelog Priority Rules
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Rules of priority for substituents used in the EZ and SR notation systems
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Zaitsev's Rule
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Rule stating that the alkene formed in the greatest amount by beta-elimination is the one that corresponds to the removal of the hydrogen from the carbon having the fewest hydrogen substituents
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Syn Addition
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Reactions in which electrophiles add to the same face of a double bond
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Anti Addition
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Reactions in which electrophiles add to opposite faces of a double bond
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Stereoselectivity
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Reactions in which a single starting material can give two or more stereoisomeric products but in which one of them predominates
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Stereospecificity
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Reactions in which, when carried out with stereoisomeric starting materials, products are formed from one reactant that are stereoisomers of the products formed from the other reactant
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Markovnikov's Rule
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Rule that states that when an unsymmetrically substituted alkene reacts with a hydrogen halide, the hydrogen adds to the carbon that has the greater number of hydrogen substituents, and the halogen adds to the carbon having fewer hydrogen substituents
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Peroxide Effect
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Conditions in which free radical addition of HBr to alkenes yields anti-Markovnikov products
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Principle of Microscopic Reversibility
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In any equilibrium process, the sequence of intermediates and transition states encountered as reactants proceed to products in one direction must also be encountered in precisely the reverse order in the opposite direction
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Hydroboration Oxidation
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Reaction of alkenes with boranes, and then subsequently with hydrogen peroxide and base to yield anti-Markovnikov alcohols
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Vicinal
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Adjective that describes substituents on adjacent carbons
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Geminal
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Adjective that describes substituents on the same carbon
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Ozonolysis
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Reaction of alkenes with ozone to yield ozonides, which are then cleaved by water to yield two carbonyls
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Enantiomers
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Stereoisomers that are nonsuperimposable mirror images of each other
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Specific Rotation
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The quantity that describes the tendency of an enantiomer to rotate plane-polarized light
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Optical Purity
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Percent enantiomeric excess
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Diastereomers
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Stereoisomers that are not enantiomers (one stereocenter's configuration differs the other, but the second stereocenters have the same configuration, like RR and RS)
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Erythro
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Diastereomer in which like substituents are on the same side of the Fischer projection
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Threo
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Diastereomer in which like substituents are on opposite sides of the Fischer projection
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Meso
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A combination of stereocenters that yields this type of compound compound that is achiral (it has a plane of symmetry that passes through the molecule)
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Resolution
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Separation of a racemic mixture into its enantiomeric components
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Isotactic
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Polymers in which side groups are all on the same side of the polymer chain
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Syndiotactic
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Polymers in which side groups are on alternating sides of the polymer chain
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Atactic
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Polymers in which side groups are randomly distributed on both sides of the polymer chain
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Inversion of Configuration
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Back-side attack; nucleophile attacks a substrate from the side opposite from that of the leaving group; also known as Walden _____
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Solvolysis
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Substitution reactions in which the nucleophile is the solvent
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Cyclooctyne
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Smallest stable cycloalkyne
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Carbanion
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Conjugate base of a hydrocarbon or a compound with negatively charged carbon
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Lindlar Catalyst
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Catalyst used for the semihydrogenation of alkynes to alkenes; palladium on calcium carbonate combination with PbC₂H₃O₂ and quinoline that poison the catalyst
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Isolated
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Dienes in which the double bonds are separated from each other by one or more sp³ hybridized carbons
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Conjugated
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Dienes in which the double bonds are connected to each other by a single bond
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Cumulated
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Dienes in which one carbon atom is common to two carbon-carbon double bonds
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Allenes
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Cumulated dienes
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1,2 Addition
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Direct addition to conjugated dienes; no allylic shift occurs
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1,4 Addition
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Conjugate addition to conjugated dienes; allylic shift occurs
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Diels Alder Reaction
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Conjugate addition of an alkene (dienophile) to a diene; always forms a ring
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Pericyclic
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One-step reaction that proceeds through a cyclic transition state
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Electrocyclic
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Reaction in which a sigma bond is formed between the ends of a conjugated π electron system (or the reverse)
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Arenes
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Common name for aromatic hydrocarbons
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Birch Reduction
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Dissolving metal reductions; reaction of benzene with metal to yield cyclohexadiene and the metal's cation
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Hückel's Rule
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Among planar, monocyclic, fully conjugated polyenes, only those possessing (4n + 2) π electrons will have special aromatic stability
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Annulene
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Completely conjugated monocyclic hydrocarbons
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Pyridine
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Basic heterocyclic aromatic compound with formula C₅H₅N
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Pyrrole
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Weakly basic heterocyclic aromatic compound with formula C₄H₅N
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Furan
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Heterocyclic aromatic compound with formula C₄H₄O
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Thiophene
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Heterocyclic aromatic compound with formula C₄H₄S
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Electrophilic Aromatic Substitution
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Reaction of aromatic compounds: ArH + EY → ArE + HY
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Cyclohexadienyl
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Also known as the arenium ion, of form C₆H₆E⁺ where E is an electrophile
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Friedel Crafts Reaction
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Synthetic method of alkylation of benzene from an alkyl halide in the presence of a Lewis acid, such as AlCl₃ or FeBr₃
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Grignard Reagents
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Organometallic reagents of form RMgX, useful in the preparation of alcohols
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Retrosynthetic Analysis
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Method of synthesis in which one reasons backwards from the target molecule to suitable starting materials, championed by E. J. Corey
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Gilman Reagents
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Organometallic reagents of form R₂CuLi, useful in synthesizing large organic molecules
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Simmons Smith Reaction
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Synthetic reaction for the preparation of cyclopropanes from alkenes using iodomethylzinc iodide (ICH₂ZnI)
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Carbene
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Neutral molecules in which one of the carbon atoms has six valence electrons (two bonds and one lone pair)
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Carbenoids
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Molecules that behave like carbenes in chemical reactions
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Oxymercuration Demercuration
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Conversion of alkenes to alcohols using mercury (II) acetate by way of β-hydroxyalkylmercury (II) acetate
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Hydroxylation
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Addition of two hydroxyl groups to a double bond forming a diol, such as the reaction of alkenes with osmium tetraoxide (OsO₄)
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Fischer Esterification
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Acid-catalyzed condensation of an alcohol and a carboxylic acid
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Mercapto
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Formal name for the sulfhydryl group (known as thiol when it is the main functional group), -SH
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Disulfides
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Name for the functional group R-S-S-R
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Alkoxy
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Substitutive name for the ether functional group, R-O-R
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Crown Ethers
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Macrocyclic polyethers, cyclic compounds containing 4 or more ether linkages in a ring of 12 or more atoms; useful for dissolving ions in nonpolar solvents
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Williamson Ether Synthesis
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Synthesis of ethers by the nucleophilic substitution of an alkyl halide by an alkoxide anion
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Sulfone
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Functional group containing the unit R-SO₂-R
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Sulfonium
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Ions of the general form R₃S⁺
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Hydroformylation
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Reaction converting alkenes to aldehydes containing an additional carbon atom; reacted with CO and H₂ in the presence of a cobalt or rhodium based catalyst
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Cyanohydrin
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Compounds containing cyano and hydroxyl groups bonded to the same carbon
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Hemiacetal
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Compound containing a hydroxyl group and an ether bonded to the same carbon
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Acetal
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Compound containing geminal ether groups (geminal diethers), prepared by the treatment of aldehydes with alcohols
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Carbinolamine
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Compound containing a hydroxyl group and an amine group on the same carbon
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Imine
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Compound containing a carbon double bonded to a nitrogen (R₂C=NR)
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Enamine
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Compound containing a carbon double bonded to another carbon and single bonded to an amine group (R₂C=CR(NR₂))
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Wittig Reaction
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Synthesis of alkenes from the reaction of aldehydes or ketones with phosphorus ylides
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Ylide
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Neutral molecules that have two oppositely charge atoms, each with an octet of electrons, directly bonded to each other
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Baeyer-Villiger Oxidation
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Reaction of ketones and peroxy acids to yield esters and carboxylic acids
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Enolate
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Conjugate base of a carbonyl compound (R₂C=CRO⁻)
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Aldol Addition
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Reaction of two aldehydes to yield a compound containing both an aldehyde functional group and a hydroxyl group
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Aldol Condensation
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Reaction of aldol addition followed by an elimination reaction, yield α,β-unsaturated aldehydes and water
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Nucleophilic Substitution
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Reaction of the form Nu + R₃C(Lg) → NuCR₃ + Lg
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Lipophilic
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Fat-loving
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Nitriles
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Alkyl cyanides, of the form RCN
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Decarboxylation
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Reaction of carboxylic acids to yield alkanes and carbon dioxide
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Carboxamides
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Name for acyl amines
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Lactones
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Cyclic esters
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Lactams
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Cyclic Amides
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Imide
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Two acyl groups bonded to a single nitrogen
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Carbamic Acid
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Carboxylic acids in which the R group is an amine
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Aniline
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Amino-substituted derivatives of benzene
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Kolbe Synthesis
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Reaction of sodium phenoxide with carbon dioxide to yield salicylic acid
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