Alcohols Flashcards
Describe the structure of a phenol
A benzene ring with hydroxyl groups
Alcohols have high boiling points due to
the ability to hydrogen bond
Because alcohols can hydrogen bond it increases their
solubility and boiling points
Alcohols can dissociate into
protons (H+) and alkoxides (RO-)
Phenols are the most acidic alcohols because
the aromatic ring can delocalize the charge of the conjugate base
Primary alcohols can be oxidized to aldehydes by
Pyridinium Chlorochromate (PCC)
Primary alcohols can be fully oxidized to ________ by ________
Carboxylic Acids, strong oxidizing agents
Strong oxidizing agents include what ?
A metal bound to a lot of oxygens
Describe a Jones Oxidation
When chromium trioxide is dissolved with dilute sulfuric acid in acetone to oxidize primary alcohols to carboxylic acids and secondary alcohols to ketones
What are the functions of mesylates and tolsylates?
To make alcohol into a better leaving group
To protect alcohol from reacting
Aldehydes and ketones can be protected by converting them into ______ or ______ using________
acetals or ketals, diols
One equivalent of alcohol reacting with an aldehyde forms a
hemiacetal
One equivalent of alcohol reacting with a ketone forms a
hemiketal
An acetal or ketal can be reverted back to an aldehyde or ketone (carbonyl) by
an aqueous acid, deprotection
In the presence of water and oxidizing agents, aldehydes and ketones form
geminal diols
What is a geminal diol
a molecule that is two parts alcohol
Describe the structure of a phenol
An aromatic ring with hydroxyl groups attached
What increases the boiling point of alcohols
More hydroxyl groups which are capable of hydrogen bonding
Why does p-ethylphenol have a lower pKa than ethanol?
p-ethylphenol has a ring structure making it resonance stabilized so its a stronger acid
What is PCC in organic chemistry? What is it used for?
Pyridinium Chlorochromate, oxidizes alcohols
Aldehydes are rapidly hydrated to form______ that can be oxidized to carboxylic acids?
Geminal Diols
How are mesylates formed?
Using methylsplfonyl chloride and alcohol in the presence of a base
T/F Hydroxyl groups of alcohols are poor leaving groups for nucleophilic substitution reactions
True
Acetals and Ketals protect aldehydes and ketones from reacting because they do not react with
Lithium Aluminum Hydride
Carbonyls react strongly with _______ agents like LiAlH4
Reducing
By reacting a ______ with a ketone or aldehyde it protects that group from reacting with a reducing agent because LiAlH4 reacts strongly with _____
Diol, Carbonyl
Treatment of phenols with oxidizing agents produces
Quinones
Describe the structure of a quinone
A conjugated ring with carbonyls
What is the difference in structure between a phenol and a hydroquinone
Phenols have one OH group
Hydroquinone have two OH groups
Are quinones electrophiles or nucleophiles?
Electrophiles
Quinones act as electron ________-
acceptors
Oxidation of phenols forms
quinones
Oxidation of Quinones forms
Hydroxyquinones
Quinone structures are characterized by
An aromatic ring with Carbonyl groups attached
Hydroquinones can be oxidized to_____ which can be further oxidized to________
Quinones, Hydroxyquinones
How do quinones and hydroxyquinones differ?
The presence of a hydroxyl group on a ring
Are electron donating molecules are electrophilic or nucleophilic?
Nucleophilic
If a molecule is electron donating is it a nucleophile or electrophile?
Nucleophile
The resonance stabilization of quinones makes it an electron _______
donator
What charge do nucleophiles have ?
Positive
Are quinones electrophiles or nucleophiles?
Electrophiles
Are quinones aromatic?
No
What makes a structure aromatic?
- all atoms must be sp2 hybridized
- an odd number of pi electrons
- Planar-overlapping of pi orbitals
For a structure to be aromatic it must have an ____ number of pi electrons
Odd
What forms a hydroxyquinone?
Oxidation of a Quinone, adding a hydroxyl group
—remember oxidation increases the number of bonds to oxygen, an OH group is added
Oxidation of a quinone forms
a hydroxyquinone
Oxidation of ubiquinone forms
Ubiquinol
What characteristic of ubiquinol and ubiquininone allows it to act as an electron carrier in the phospholipid bilayer?
The long alkyl chain which is lipid soluble and hydrophobic like the FA tails
What are the Huckel’s Rule ‘magic numbers’
2,6,10,14
An aromatic compound has a(n) _____ number of double bonds
even
Are phenols aromatic ?
Yes
Describe how deprotection of a ketone or aldehyde occurs?
Acidic workup using a catalytic acid with water
Tertiary alcohols are oxidized with difficulty because
there is no Hydrogen on the carbon containing the alcohol to be oxidized
Why are the hydroxyl hydrogens on phenol acidic?
The resonance in the ring makes the Hydrogen acidic, if you move the double bonds around to the OH group the H can dissociate
What is used to remove a protecting group
A strong acid
Why are bases good leaving groups?
Because they are more stable with an extra set of electrons
What is a leaving group?
The molecule that keeps the electrons after heterolysis
