Electrophilic Aromatic Substitution
Synthesis Questions
Conceptual Questions
Aldehyde-Ketone Mechanisms
Reaction Mechanism Basics
100
If the charge on the sigma complex is positive, would a Electron Donating or Withdrawing group stabilize it?
Electron DONATING group
100
What does the following reagent do?
KMnO4, Heat, -OH
100
Two concepts that describe stability in organic chemistry.
Inductive Effect
Resonance Effect
100
Why are carbonyl carbons electrophilic?
Location next to electronegative oxygen (see resonance structure)
100
An electron deficient species that is likely to accept lone pair electrons from another molecule
Electrophile
200
The stability of which reaction intermediate determines how "fast" a EAS reaction goes.
Sigma complex
200
Reaction conditions for a reduction
Zn(s), HCl
Sn(s), HCl
Fe(s), HCl
200
What does it mean for an electron donating group to be donating via resonance.
You can draw additional resonance structures using the lone pairs from the group
200
The purpose of OH- and H3O+ in Carbonyl Chemistry
OH- generates stronger nucleophiles
H3O+ generates a stronger electrophile (protonation of carbonyl)
200
Electron rich species that can give electrons to electron poor species in a reaction mechanism.
Nucleophiles!
300
Friedel crafts alkylation are unreliable for what reasons?
Adds an electron donating group, so multiple additions occur.
Rearrangements of carbocation can occur.
300
In a synthesis, we try to perform a Friedel Crafts Acylation to the following molecule. Why is this a bad idea:
Ring is too strongly deactivated for a Friedel Crafts reaction.
300
Acetone is a liquid at room temperature. Describe the intermolecular forces acetone has, and why does it have a lower boiling point than water?
Acetone has only dipole dipole intermolecular forces, therefore is more volatile. Water is capable of H-bonding due to extremely polar O-H bond.
300
List of nucleophiles and electrophiles involved in Imine/Acetal Formation AND Hydrolysis.
Electrophile --> Carbonyl carbon and carbon double bonded to imine.
Nucleophile --> Any electronegative atom (nitrogen, oxygen).
300
Under Acidic conditions, what chemical species should NOT be drawn in the mechanism.
Any base, or anything with a negative charge on it.
400
Draw two electrophiles that are involved in EAS reaction mechanisms.
(Note: There are more)
400
Why can't we make the following molecule from toluene in one step:
Methyl group is Ortho/Para directing, but chlorine is added Meta. We would have to convert Methyl group into Meta Director (via oxidation) then reduce (reduction).
400
If two "directing" groups are on an aromatic ring, who wins:
Stronger Electron Donating group
OR Stronger EWG (resonance stabilized always wins)
400
The general steps do the aldehyde/ketone mechanisms follow.
Acid: Protonation --> Nucleophilic Attack --> Deprotonation
Base: Deprotonation --> Nucleophilic Attack --> Protonation
400
Identify the nucleophile, base, and electrophile in the following mechanism:
Green is nucleophile in first step.
Water is base in second step.
Carbonyl carbon behaves as the electrophile
500
A weakly deactivating O/P director
Chloro group
500
In order to add a chloro group Ortho to methyl group on toluene with a good yield what sequence of reactions would we use.
1) Sulfonation
2)Chlorination
3)treat with hot acid (remove sulfonyl group)
500
Relative to acetone, the following molecule has a higher or lower Khyd.
Khyd would be higher (products over reactants for K).Hydrate formation is favorable due to lack of electron donating alkyl groups and a EWG (trifluoromethyl).
500
Draw the first mechanistic step for the hydrolysis of an acetal under acidic conditions:
First Step sees protonation of acetal
500
Draw out a nucleophile and describe why it is nucleophilic
Any oxygen compound, grignard reagent, aromatic ring (if it has electrons it is good to go)