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ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
CONCEPT: ALCOHOL NOMENCLATURE
□ Glycols: Alcohols with two hydroxyls are called ___________; with three hydroxyls are called ____________
● Always give most priority to the –OH group.
EXAMPLE: Provide the correct common and IUPAC name of the following alcohols.
a.
b.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: INTRO TO REDOX
● Oxidation reactions involve an increase in the ______________ content of a molecule
● Reduction reactions involve an increase in the ______________ content of a molecule
EXAMPLE: Label the following transformations as oxidation or reduction.
a.
b.
c.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: OXIDATION
□ Oxidizing agents are used to oxidize molecules
● Most oxidizing agents add as much oxygen as possible while not breaking ANY C-C bonds.
EXAMPLE: Which of the following compounds could be oxidized?
□ These are called strong oxidizing agents. They include KMnO4 and the Cr6+ reagents (H2Cr2O4, CrO3, K2Cr2O7, etc.)
EXAMPLE: Draw the products of the previous molecules with a strong oxidizing agent
□ PCC is a weak oxidizing agent. It reacts similar but can only add ____ equivalent of oxygen to 1º alcohols.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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PRACTICE: Provide the major product for the following oxidation reaction.
CH3
CH3 CH3
OHOH
OH PCC
CH2Cl2
PRACTICE: Provide the major product for the following oxidation reaction.
CH3CH2 1. O3
2. Zn, CH3CO2H
PRACTICE: Provide the major product for the following oxidation reaction.
KMnO4
H+
OH
OH
OH
PRACTICE: Provide the major product for the following oxidation reaction.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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PRACTICE: Determine the major product for the following reaction.
PRACTICE: Determine the major product for the following reaction.
PRACTICE: Provide the necessary reagents for the following transformation.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: REDUCTION
□ Reducing agents are used to reduce molecules
● These reagents add hydrogens across π-bonds. Unsaturated hydrocarbons and carbonyls can be reduced.
General Mechanism: Nucleophilic addition of hydrogen
□ Reducing agents add to ALL π-bonds present. Multiple equivalents of hydrogen will react if possible.
● LiAlH4 is a strong reducing agent. It is able to reduce ANY carbonyl compound into alcohol
EXAMPLE: Draw the products of the following molecules reacted with LiAlH4
□ NaBH4 is a weak reducing agent. It can only add ____ equivalent of oxygen and can only reduce CHO and ketones
EXAMPLE: Draw the products of the following molecules reacted with NaBH4
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: NUCLEOPHILIC ADDITION
□ One of the most important ways that carbonyl compounds react is through nucleophilic addition.
● The carbonyl carbon is _____________________________
Nucleophilic Addition General Mechanism:
Nucleophilic Addition General Reactions:
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: PREPARATION OF ORGANOMETALLICS
□ Organometallics are alkylating agents that have mostly group IA or group IIA metals bonded to a carbon structure
● They can also react as strong ____________. Beware of cross-reactions with acidic hydrogens.
1. Sodium Alkynides
2. Grignard Reagents
3. Organolithium Reagents
4. Gilman Reagents
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: REACTIONS OF ORGANOMETALLICS
1. Substitution/Elimination on Alkyl Halides
2. Nucleophilic Addition on Ketones and Aldehydes
3. Nucleophilic Acyl Substitution on Esters
4. Base-Catalyzed Epoxide Ring Opening
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: USE OF PROTECTING GROUPS
□ Organometallics are powerful bases. They will react with any acidic protons available, ruining the reagent.
We can use tert-butyl or silyl ethers to protect alcohols from deprotonation by organometallic reagents
● p-Toluenesulfonic acid is an acid commonly used for this step (abbrev. TsOH or pTSA)
EXAMPLE: Provide the mechanism and final product for the following transformation
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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PRACTICE: Predict the product of the following reaction.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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PRACTICE: Predict the product of the following reaction.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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PRACTICE: Predict the product of the following reaction.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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PRACTICE: Predict the product of the following reaction.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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PRACTICE: Propose a synthesis to accomplish the following transformation.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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PRACTICE: Propose a synthesis to accomplish the following transformation.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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PRACTICE: Propose a synthesis to accomplish the following transformation (Hint: 4 steps)
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: ACID-CATALYZED DEHYDRATION
□ Alcohols are terrible leaving groups, but in the presence of acid, they can be converted into an awesome leaving group
● The more –R groups on the alcohol, the easier to dehydrate: _________________________________
● The specific elimination mechanism depends on how easily the molecule will form a ______________________.
E2 Dehydration: 1o Alcohol Mechanism:
● Protonation:
● E2 β-Hydrogen Elimination:
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
Page 19
CONCEPT: ACID-CATALYZED DEHYDRATION
□ Alcohols are terrible leaving groups, but in the presence of acid, they can be converted into an awesome leaving group
E1 Dehydration: 2o and 3o Alcohol Mechanism:
● Protonation:
● Carbocation Formation:
● E1 β-Hydrogen Elimination:
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
Page 20
PRACTICE: Provide the mechanism and major product for the following dehydration reactions:
a.
b.
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: DEHYDRATION WITH PHOSPHORYL CHLORIDE
□ Alcohol can attack POCl3 to become a good leaving group, which can then be eliminated by base.
Mechanism:
● Nucleophilic Attack + Deprotonation
●E2 β-Hydrogen Elimination:
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: FISCHER ESTERIFICATION— MECHANISM
Also known as acid-catalyzed esterification, this is one of the more important mechanisms in this course.
General Reaction:
Mechanism:
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: TERT-BUTYL ETHER PROTECTING GROUPS
□ Protecting groups are used to shield reactive moieties while reactions are happening on other parts of the molecule.
● By definition, they must be completely reversible.
EXAMPLE: Will the following reaction proceed efficiently as drawn? Why or why not?
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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t-Butyl Ether: ● Addition of isobutylene through reversible acid-catalyzed alkoxylation
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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CONCEPT: SILYL ETHER PROTECTING GROUPS
□ A group used to protect alcohols are silyl (silicon) chlorides.
Mechanism: ● TBDMS is the most common silyl chloride in Organic Chemistry 1
EXAMPLE: Predict the product of the following reaction
ORGANIC - MCMURRY 9E
CH. 17 - ALCOHOLS AND PHENOLS
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