Exam 2 (Information) Flashcards
Double bonds separated by one single bond
Conjugated
p orbitals on 3 or more C,N, or O atoms in a row in the same plane
Conjugated
A compound containing two adjacent (next to) pi nonds
Cumulated
Double bonds are
Nucleophilic and attack the electrophil
The product that forms the fastest forms the most
Kinetic Control
Equilibrium is asserted and the most stable product predominates over time
Thermodynamic Control
A reaction for which the product distribution is determined by the relative rates at which the products are formed
Kinetic Control
A reaction for which the ratio of products is determined solely b the distribution of energy among the products
Thermodynamic Control
At low temperatures, only few molecules have energy greater than Ea (1,4) so most
1,2 products form
At high temperatures, first 1,2 product is formed, THEN
1,2 product reforms the intermediate and an equilibrium forms and some starts forming 1,4 product and is stuck there. As time passes, more 1,4 product forms and will predominate.
Mechanism-less Reaction
Pericyclic Reactions
Most common pericyclic reaction
Cycloaddition (Diels-Alder)
Pericyclic Reactions (3)
Cycloaddition (Diels-Alder), Electrocyclization, and Sigmatropic Rearrangement
A bond theory that treats a bond as the sharing of electrons that are associated individual atoms, rather than bing associated with the entire molecule
Valence Bond Theory (partial charges)
A description of bonding in terms of molecular orbitals, which are orbitals associated with an entire molecule rather than an individual atom
Molecular Orbital Theory (orbitals in and out of phase)
Orbitals in phase
Bond
Orbitals out of phase
Antibond or Repulsion
The analysis of a reaction using Molecular Orbit Theory, where only the frontier orbitals (HOMO and LUMO) are considered
Frontier Orbital Theory
The highest occupied molecular orbital
HOMO
The lowest unoccupied molecular orbital
LUMO
The highest occupied molecular orbital and the lowest unoccupied molecular orbital that participate in a reaction
Frontier orbitals
Dienes and dienophiles form no reaction when
only heat is present
[4+2] Cycloaddition
Diels Alder
hv changes
HOMO and LUMO
A compound that possesses chirality centers and an internal plane of symmetry
meso compound
A cis dienophile added to a cis diene
makes a meso compound
A cis diene added to a trans dienophile
makes enatiomers (2 products)
Other functional groups that can be dienophiles
C trpl C, C trpl N
In Diels Alder reactions that produce bicyclic structures, the positions that are anti to the larger bridge
exo
In Diels Alder reactions that produce bicyclic structures, the positions that are syn to the larger bridge
endo
Trans to each other, lower energy, thermodynamic product at hight temp, higher Ea, no pi stacking
Exo
Two groups pointing toward each other, Kinetic product (forms faster), cold, Lower Ea due to pi stacking
Endo
Lower energy put off
more stable
Aromatic if:
- Cyclic
- Every atom in ring must be part of the same conjugated system
- Huckels rule: 4n+2=pi e- (n must be whole number)
Obeys rules one and two of aromaticity rules but not three
Antiaromatic
For antiaromatic to be stable
it resists conjugation and is flat
Aromatic structures that contain N, O, S, NH, or a lone pair
Heteroaromatic Compounds
Compounds containing multiple aromatic rings fused together
Polycyclic Aromatic Hydrocarbons (PAHs)
1,2 substituents
Ortho-
1,3 substituents
Meta-
1,4 substituents
Para-
A substitution reaction in which an aromatic proton is replaced by an electrophile and the aromatic moiety is preserved
Electrophilic Aromatic Substitution (EAS)
A compound capable of functioning as an electron pair acceptor
Lewis Acid
The positively charged intermediate of an electrophilic aromatic substitution reaction
Sigma Complex
An electrophilic aromatic substitution reaction in which an SO3H group is installed on an aromatic ring
Sulfonation
An electrophilic aromatic substitution reaction that involves the installation of a nitro group (NO2) on an aromatic ring
Nitration
An electrophilic aromatic substitution reaction that installs an acyl group on an aromatic ring
Friedel-Crafts Acylation
The term describing a carbonyl group (C=O) connected to an alkyl group (no pi bonds; only C and H) or an aryl group (aromatic ring)
Acyl Group
An electrophilic aromatic substitution reaction that installs an alkyl group on an aromatic ring
Friedel-Crafts Alkylation
A substituent lacking pi bonds and comprised of only carbon and hydrogen atoms
Alkyl
Transition metals + Acid =
Good Reducing Agents
Ex) Br2/FeBr3 - - Only adds O and P
Electron Poor, Electron Withdrawing Group
Deactivated
Ex) N(+)O2
Electron Rich, Electron Donating Group
Activating
Ex) N(lone pair)H2
Usually deactivating
Meta Directing
Electron Withdrawing Groups (EWGs)
Usually activating
Ortho and Para Directing
Electron Donating Groups (EDGs)
If atom attached to ring is + charged
Strongly Deactivating
If atom attached to ring has a partial + charge due to resonance
Moderately Deactivating
If atom attached to benzene has a lone pair
Strongly activating
Alkyl groups
Weakly activating
Deactivating groups can only add
one at a time
Strong electron withdrawing group (resonance stabilized )
SNAr
Elimination/Addition (Dow Process)
Benzyne (No strong EWGs)
Nu- (either NH2 or OH or OR)
NO2 and CL
SNAr
Cl
Can do Diels Alder
Benzyne
The withdrawal of electron density that occurs when a bond is shared by two atoms of differing electronegativity
Induction
Increase up and to the right on the periodic table
Electronegativity
