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Chapter 17. Alcohol & Phenol ROH & ArOH. Chapter 17. Naming Properties Synthesis Reactions. 5-methyl-2,4-hexanediol. 2-methyl-4-phenyl-2-butanol. 4,4-Dimethylcyclohexanol. trans -2-Bromocyclopentanol. 4-Bromo-3-methyl-phenol. ( o = ortho(1,2), m = meta(1,3), p = para(1,4)).

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Chapter 17 l.jpg

Chapter 17

Alcohol & Phenol

ROH & ArOH

Chapter 17 - Alcohol & Phenol


Chapter 172 l.jpg
Chapter 17

  • Naming

  • Properties

  • Synthesis

  • Reactions

Chapter 17 - Alcohol & Phenol


Slide3 l.jpg

5-methyl-2,4-hexanediol

Chapter 17 - Alcohol & Phenol


Slide4 l.jpg

2-methyl-4-phenyl-2-butanol

Chapter 17 - Alcohol & Phenol


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4,4-Dimethylcyclohexanol

Chapter 17 - Alcohol & Phenol


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trans-2-Bromocyclopentanol

Chapter 17 - Alcohol & Phenol


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4-Bromo-3-methyl-phenol

Chapter 17 - Alcohol & Phenol


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(o = ortho(1,2), m = meta(1,3), p = para(1,4))

2-(2-Hydroxyethyl)phenol

o-(2-Hydroxyethyl)phenol

Chapter 17 - Alcohol & Phenol


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Chapter 17

  • Naming

  • Properties

  • Synthesis

  • Reactions

Chapter 17 - Alcohol & Phenol


Properites l.jpg
Properites

  • Hydrogen bonding

  • Acidity and Basicity

Chapter 17 - Alcohol & Phenol


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Hydrogen Bonding

H2O

HF

H2Te

NH3

H2Se

H2S

SnH4

…extrapolation

GeH4

SiH4

CH4

1. Water, HF, and NH3 show unusually high bp.

2. Dotted lines depict bp if there were no H-bonding.

3. All others follow normal trend.

Chapter 17 - Alcohol & Phenol


Slide12 l.jpg

Chemical Bond,

intramolecular,

150 - 600 kJ/mol

Hydrogen bond,

intermolecular,

4 - 25 kJ/mol

Hydrogen Bonding in Water

+

+

+

+

--

--

+

+

--

+

+

+

--

+

--

Chapter 17 - Alcohol & Phenol


Slide13 l.jpg

Hydrogen Bonding in Alcohol

+

+

-

-

+

-

+

+

-

-

Chapter 17 - Alcohol & Phenol


Hydrogen bonding and boiling point l.jpg
Hydrogen Bonding and Boiling Point

Chapter 17 - Alcohol & Phenol


Properites15 l.jpg
Properites

  • Hydrogen bonding

  • Acidity and Basicity

Chapter 17 - Alcohol & Phenol


Acidity basicity l.jpg
Acidity & Basicity

Like water, alcohol can act as an acid or as a base.

base

acid

oxonium ion

alkoxide ion

acid

base

phenoxide ion

Chapter 17 - Alcohol & Phenol


Slide17 l.jpg

1. Why does the reaction shift to the right?

2. Why is phenoxide ion stable?

3. Why is phenol acidic (compare to water)?

…….

Chapter 17 - Alcohol & Phenol


Resonance stability acid strength l.jpg

2. Stable anion implies the following reaction will proceed to the right,

Resonance, Stability, Acid Strength

1. Resonance structures implies stability.

3. Stable anion also implies that phenol is a stronger acid than water.

Chapter 17 - Alcohol & Phenol


Slide19 l.jpg

Substituted Phenol to the right,

Which one is more acidic and why?

Chapter 17 - Alcohol & Phenol


Slide20 l.jpg

To examine the acid strength, to the right,

Chapter 17 - Alcohol & Phenol


Resonance stability acid strength21 l.jpg

1. to the right,

has more resonance structures than

,so it is more stable.

.

3. Since 1 is true, that means

is more reactive than

.

4. Since 3 is true,

is more acidic than

Resonance, Stability, Acid Strength

2. Fifth structure shows that nitro is an electron-withdrawing group.

5. See page 663 for para position effect.

Chapter 17 - Alcohol & Phenol


Resonance stability acid strength22 l.jpg

pK to the right,a

9.95

10.17

Resonance, Stability, Acid Strength

1. Phenol is more acidic than p-methylphenol.

2. pKa indicates that CH3– is an electron-donating group.

Chapter 17 - Alcohol & Phenol


Arrange the order of acidity from highest to lowest of the following compounds and explain why l.jpg
Arrange the order of acidity (from highest to lowest) of the following compounds and explain why.

Chapter 17 - Alcohol & Phenol


Slide24 l.jpg

Answer Key following compounds and explain why.

4-methoxylphenol

(least acidic)

phenol

4-nitrobenzylphenol

(most acidic)

Reason: The nitro- on4-nitrobenzylphenol is an electron-withdrawing group

which enhances the aciditiy compare to phenol. The methoxy- of

4-methoxylphenol is an electron-donating group, thus it is less acidic than

phenol.

Chapter 17 - Alcohol & Phenol


Chapter 1725 l.jpg
Chapter 17 following compounds and explain why.

  • Naming

  • Properties

  • Synthesis

  • Reactions

Chapter 17 - Alcohol & Phenol


Synthesis l.jpg
Synthesis following compounds and explain why.

  • Hydroboration, Oxymercuration, Hydroxylation.

  • Reaction with peroxide.

  • Reduction of carbonyl compounds.

Chapter 17 - Alcohol & Phenol


Slide27 l.jpg

HX following compounds and explain why.

ether

X2

CH2Cl2

KMnO4, H3O+

X2

O3

H2O(xs)

Zn/H3O+

HgAc2, H2O/THF

CH2I2

NaBH4

Zn(Cu) ether

BH3, THF

CHCl3

H2O2, OH-

KOH

H2

OsO4

NaHSO4, H2O

Pd or Pt

M

halogenation

anti

halohydrination

oxidation

M

anti

oxymercuration

M

oxidation

Alkene

hydroboration

non-M

syn

Simmons-Smith

syn

hydrogenation

syn

carbenation

syn

syn

hydroxylation

Chapter 17 - Alcohol & Phenol


Synthesis28 l.jpg
Synthesis following compounds and explain why.

  • Hydroboration, Oxymercuration, Hydroxylation.

  • Reaction with peroxide.

  • Reduction of carbonyl compounds.

Chapter 17 - Alcohol & Phenol


Also from alkene l.jpg
Also from alkene following compounds and explain why.

1-Methyl-1,2-epoxy-

cyclohexane

1-Methyl-

trans-1,2-cyclohexanol

Chapter 17 - Alcohol & Phenol


Synthesis30 l.jpg
Synthesis following compounds and explain why.

  • Hydroboration, Oxymercuration, Hydroxylation.

  • Reaction with peroxide.

  • Reduction of carbonyl compounds.

Chapter 17 - Alcohol & Phenol


Reduction of aldehyde ketone l.jpg
Reduction of Aldehyde & Ketone following compounds and explain why.

Reducing Agents:

1. NaBH4, ethanol, H+

2. LiAlH4, ether, H+

Chapter 17 - Alcohol & Phenol


Reduction of carboxylic acid ester l.jpg
Reduction of Carboxylic Acid & Ester following compounds and explain why.

Reducing Agents:

LiAlH4, ether, H+

Chapter 17 - Alcohol & Phenol


Carbonyl compounds grignard reagent l.jpg
Carbonyl compounds + Grignard reagent following compounds and explain why.

Chapter 17 - Alcohol & Phenol


Chapter 1734 l.jpg
Chapter 17 following compounds and explain why.

  • Naming

  • Properties

  • Synthesis

  • Reactions

Chapter 17 - Alcohol & Phenol


Reactions l.jpg
Reactions following compounds and explain why.

  • Dehydration  alkenes

  • With HX  alkyl halides

  • With Tosylates

  • Oxidation - 1o, 2o, & 3o

  • Protection of alcohol

Chapter 17 - Alcohol & Phenol


Synthesis of alkene l.jpg
Synthesis of Alkene following compounds and explain why.

From halides - dehydrohalogenation (minus HX):

Elimination

From alcohol - dehydration (minus H2O):

Chapter 7 slide 5

Chapter 17 - Alcohol & Phenol


Dehydration l.jpg
Dehydration following compounds and explain why.

1. Watch for Zaitsev’s rule!!!

2. Only 3o alcohols are readily dehydrated with acid.

3. 2o alcohols are dehydrated under mild basic condition.

4. Alcohol dehydration via E2.

Chapter 17 - Alcohol & Phenol


Dehydration mechanism l.jpg
Dehydration Mechanism following compounds and explain why.

E1

Chapter 17 - Alcohol & Phenol


Reactions39 l.jpg
Reactions following compounds and explain why.

  • Dehydration  alkenes

  • With HX  alkyl halides

  • With Tosylates

  • Oxidation - 1o, 2o, & 3o

  • Protection of alcohol

Chapter 17 - Alcohol & Phenol


Alcohol to alkyl halide l.jpg
Alcohol to Alkyl Halide following compounds and explain why.

SN2

Chapter 17 - Alcohol & Phenol


Reactions41 l.jpg
Reactions following compounds and explain why.

  • Dehydration  alkenes

  • With HX  alkyl halides

  • With Tosylates

  • Oxidation - 1o, 2o, & 3o

  • Protection of alcohol

Chapter 17 - Alcohol & Phenol


P toluenesulfonyl chloride p toscl l.jpg
p following compounds and explain why.-toluenesulfonyl Chloride (p-TosCl)

ROTos

Chapter 17 - Alcohol & Phenol


With tosylate l.jpg
With Tosylate following compounds and explain why.

C–O broken

Inversion

Inversion

R

S

R

C–O not broken

No inversion

Inversion

S

R

R

Chapter 17 - Alcohol & Phenol


Reactions44 l.jpg
Reactions following compounds and explain why.

  • Dehydration  alkenes

  • With HX  alkyl halides

  • With Tosylates

  • Oxidation - 1o, 2o, & 3o

  • Protection of alcohol

Chapter 17 - Alcohol & Phenol


Oxidation primary alcohol l.jpg

aldehyde following compounds and explain why.

Pyridinium chlorochromate

carboxylic acid

(an aldehyde may be an intermediate but usually can’t be isolated.)

Oxidation - Primary Alcohol

Chapter 17 - Alcohol & Phenol


Oxidation secondary alcohol l.jpg
Oxidation - Secondary Alcohol following compounds and explain why.

Chapter 17 - Alcohol & Phenol


Oxidation tertiary alcohol l.jpg
Oxidation - Tertiary Alcohol following compounds and explain why.

No Reaction

Chapter 17 - Alcohol & Phenol


Reactions48 l.jpg
Reactions following compounds and explain why.

  • Dehydration  alkenes

  • With HX  alkyl halides

  • With Tosylates

  • Oxidation - 1o, 2o, & 3o

  • Protection of alcohol

Chapter 17 - Alcohol & Phenol


Protection of alcohol l.jpg
Protection of Alcohol following compounds and explain why.

“It often happens, particularly during synthesis of complex

molecules, that one functional group in a molecule

interferes with an intended reaction on a second functional

group elsewhere in the same molecule.” - p 682.

Chapter 17 - Alcohol & Phenol


Trimethylsilyl tms ether l.jpg

Triethylamine following compounds and explain why.

Trimethylsilyl (TMS) ether

Chlorotrimethylsilane

TMS ether

ROH is now blocked or protected!!!

Chapter 17 - Alcohol & Phenol


Step 1 adding protection group l.jpg
Step 1: Adding Protection Group following compounds and explain why.

+

Chapter 17 - Alcohol & Phenol


Step 2a carrying out reaction l.jpg
Step 2a: Carrying Out Reaction following compounds and explain why.

Chapter 17 - Alcohol & Phenol


Step 2b carrying out reaction l.jpg
Step 2b: Carrying Out Reaction following compounds and explain why.

+

Chapter 17 - Alcohol & Phenol


Step 3 removing protection group l.jpg
Step 3: Removing Protection Group following compounds and explain why.

+

Chapter 17 - Alcohol & Phenol