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Review of Reactions 623
REVIEW OF REACTIONS
Preparation of Alkoxides
NaROROH NaHor Na
@ !
Preparation of Alcohols via Reduction
R H
O
R H
O
H
H
NaBH4 , MeOH
1) LAH
2) H2O 
H2
Pt, Pd, or Ni
H2
Pt, Pd, or NiRR
O
RR
OH
NaBH4 , MeOH
1) LAH
2) H2O 
R OH
O
R OH
1) Excess LAH
2) H2O 
R OMe
O
R OH
MeOH+
1) Excess LAH
2) H2O 
Preparation of Alcohols via Grignard Reagents 
O OH
R
1) RMgX 
2) H2O 
R
O
OMe R
OH
R
R
1) Excess RMgX
2) H2O 
MeOH+
Protection and Deprotection of Alcohols
TMSCl
Et3N
TBAF
R OH R O TMS
SN1 Reactions with Alcohols
R
OHR
R
R
XR
R
H2O+
HX
SN2 Reactions with Alcohols
OH
R
Br
S
HBr
PBr3
1) TsCl, py
2) NaBr
OH
R
Cl
S
SOCl2
py
HCl
ZnCl2
E1 and E2 Reactions with Alcohols
OH H2O
conc. H2SO4
Heat +
OH OTs NaOEt
TsCl
py
Oxidation of Alcohols and Phenols
With Chromic Acid
R R
O
KetoneSecondary
alcohol
R
OH
R
Na2Cr2O7
H2SO4 , H2O
R
OH
Primary
alcohol
R OH
O
Carboxylic
acid
Na2Cr2O7
H2SO4 , H2O
624 CHAPTER 13 Alcohols and Phenols
Phenol
OH O
O
Benzoquinone
Na2Cr2O7
H2SO4 , H2O
With PCC
R
OH
Primary
alcohol
R H
O
Aldehyde
PCC
CH2Cl2
REVIEW OF CONCEPTS AND VOCABULARY
SECTION 13.1
• Compounds that have a hydroxyl group (OH) are called 
alcohols.
• When naming an alcohol, the parent is the longest chain con-
taining the hydroxyl group. 
• All alcohols possess a hydrophilic region and a hydrophobic 
region. Small alcohols (methanol, ethanol, propanol) are mis-
cible with water. A substance is said to be soluble in water 
when only a certain volume of the substance will dissolve in 
a specified amount of water at room temperature. Butanol is 
soluble in water.
SECTION 13.2
• The conjugate base of an alcohol is called an alkoxide ion.
• The pKa for most alcohols falls in the range of 15–18.
• Alcohols are commonly deprotonated with either sodium 
hydride (NaH) or an alkali metal (Na, Li, or K).
• Several factors determine the relative acidity of alcohols, 
including resonance, induction, and solvating effects.
• The conjugate base of phenol is called a phenolate, or 
 phenoxide ion.
SECTION 13.3
• When preparing an alcohol via a substitution reaction, pri-
mary substrates will require SN2 conditions, while tertiary 
substrates will require SN1 conditions.
• Addition reactions that will produce alcohols include acid-
catalyzed hydration, oxymercuration-demercuration, and 
hydroboration-oxidation.
SECTION 13.4
• Alcohols can be formed by treating a carbonyl group (CRO 
bond) with a reducing agent. The resulting reaction involves 
a decrease in oxidation state and is called reduction.
• LAH is more reactive than NaBH4. In fact, LAH will reduce 
carboxylic acids and esters, while NaBH4 will not.
SECTION 13.5
• Diols are compounds with two hydroxyl groups.
• Diols can be prepared from diketones via reduction using a 
reducing agent.
• Diols can also be made via syn dihydroxylation or anti dihy-
droxylation of an alkene.
SECTION 13.6
• Grignard reagents are carbon nucleophiles that are capable 
of attacking a wide range of electrophiles, including the car-
bonyl group of ketones or aldehydes, to produce an alcohol. 
• Grignard reagents also react with esters to produce alcohols 
with introduction of two R groups.
SECTION 13.7
• Protecting groups, such as the trimethylsilyl group, can be 
used to circumvent the problem of Grignard incompatibility 
and can be easily removed after the desired Grignard reac-
tion has been performed.
SECTION 13.8
• Phenol, also called hydroxybenzene, is used as a precursor in 
the synthesis of a wide variety of pharmaceuticals and other 
commercially useful compounds.
SECTION 13.9
• Tertiary alcohols will undergo an SN1 reaction when treated 
with a hydrogen halide. 
• Primary and secondary alcohols will undergo an SN2 process 
when treated with HX, SOCl2, or PBr3 or when the hydroxyl 
group is converted into a tosylate group followed by nucleo-
philic attack. 
• Tertiary alcohols undergo E1 elimination when treated with 
sulfuric acid. 
• For an E2 process, the hydroxyl group must first be converted 
into a tosylate or an alkyl halide. 
SECTION 13.10
• Primary alcohols can undergo oxidation twice to give a car-
boxylic acid.
• Secondary alcohols are oxidized only once to give a ketone.
• Tertiary alcohols do not undergo oxidation. 
• The most common oxidizing reagent is chromic acid (H2CrO4), 
which can be formed either from chromium trioxide (CrO3) or 
from sodium dichromate (Na2Cr2O7) in aqueous acidic solution.
• PCC is used to convert a primary alcohol into an aldehyde.
SECTION 13.11
• NADH is a biological reducing agent that functions as a 
hydride delivery agent (very much like NaBH4 or LAH), while 
NAD+ is an oxidizing agent.
 SkillBuilder Review 625
• NADH and NAD+ play critical roles in biological systems. 
Examples include the citric acid cycle and ATP synthesis.
SECTION 13.12
• Phenols undergo oxidation to quinones. Quinones are 
 biologically important because their redox properties play a 
significant role in cellular respiration. 
SECTION 13.13
• There are two key issues to consider when proposing a 
 synthesis:
1. A change in the carbon skeleton
2. A change in the functional group
SKILLBUILDER REVIEW
13.1 NAMING AN ALCOHOL
STEP 1 Choose the longest 
chain containing the OH group 
and number the chain starting 
from the end closest to the 
OH group.
OH
Cl Cl
1
2
3
4
5
6
7
8
9
3-Nonanol
STEPS 2 AND 3 Identify the
substituents and assign locants. 
OH
Cl Cl
1
2
3
4
5
6
7
8
9
6-Ethyl
4,4-Dichloro
STEP 4 Assemble the
substituents alphabetically.
OH
Cl Cl
4,4-Dichloro-
6-ethyl-3-nonanol
STEP 5 Assign the 
configuration of any 
chirality center.
OH
Cl Cl
RR
(3R,6R )-4,4-dichloro-
6-ethyl-3-nonanol
Try Problems 13.1, 13.2, 13.30, 13.31a–d,f, 13.32
13.2 COMPARING THE ACIDITY OF ALCOHOLS
OHOH
More acidic
Look for resonance effects;
for example: 
OH
Cl
Cl Cl
OH
More acidic
Look for inductive effects;
for example: 
OH
OH
Less acidic
Look for solvating effects;
for example: 
Try Problems 13.5, 13.6, 13.33, 13.34
13.3 IDENTIFYING OXIDATION AND REDUCTION REACTIONS
EXAMPLE Determine
whether starting material
has been oxidized, 
reduced, or neither.
O
RO OR
STEP 1 Determine oxidation 
state of starting material. Break 
all bonds heterolytically, except 
for C C bonds.
Two electrons,
but carbon should have four.
This carbon is missing
two electrons
Oxidation state +2
CH3
C
H3C
O
STEP 2 Determine oxidation 
state of product. Break all 
bonds heterolytically, except 
for C C bonds.
Oxidation state +2
Two electrons,
but carbon should have four.
This carbon is missing
two electrons
R R
O O
CH3
C
H3C
STEP 3 Determine if there has 
been a change in oxidation state. 
This example is neither
an oxidation nor a reduction
+2 +2
Increase oxidation
Decrease reduction
No change neither
Try Problems 13.9–13.11, 13.62
626 CHAPTER 13 Alcohols and Phenols
13.4 DRAWING A MECHANISM AND PREDICTING THE PRODUCTS OF HYDRIDE REDUCTIONS
STEP 1 Draw the complete structure 
of LAH, and draw two curved arrows 
that show the delivery of hydride to 
the carbonyl group. 
STEP 2 Draw the alkoxide
intermediate. 
STEP 3 Draw two curved arrows 
showing the alkoxide intermediate 
being protonated by the proton 
source.
 
O
H
H
O
H H
O
H
Al HH
H H
O
@
@
Try Problems 13.12, 13.13, 13.46, 13.47c, 13.48e,f, 13.60
13.5 PREPARING AN ALCOHOL VIA A GRIGNARD REACTION
STEP 1 Identify the 
a position. 
OH
STEP 3 Show how each group could have been 
installed via a Grignard reaction. 
Ph Et
O
Ph
O
Me
Et
O
Me
Me
Ph Et
OH
1) MeMgBr 
2) H2O 
2) H2O 
1) PhMgBr 
1) EtMgBr 
2) H2O 
STEP 2 Identify the 
three groups connected 
to the a position.
Me
Ph Et
OH
Try Problems 13.14–13.17, 13.38, 13.40b, 13.52b–d,j,l–r, 13.58
13.6 PROPOSING REAGENTS FOR THE CONVERSION OF AN ALCOHOL INTO AN ALKYL HALIDE
STEP 1 Analyzethe substrate: 
OH
Primary = SN2
Tertiary = SN1 
Substrate is
secondary
EXAMPLE Identify 
the necessary reagents.
OH
Cl
STEP 2 Analyze 
the stereochemistry:
inversion = SN2.
OH
Cl
STEP 3 Reaction must occur via SN2 
so use reagents that favor SN2.
OH Cl
HCl
ZnCl2
SOCl2
py
1) TsCl, py
2) NaCl
Try Problems 13.19, 13.20, 13.35a–c, 13.44f, 13.52r
 SkillBuilder Review 627
13.7 PREDICTING THE PRODUCTS OF AN OXIDATION REACTION
OH
H H
Primary
STEP 1 Identify whether
the alcohol is primary or
secondary. 
O
H
Aldehyde
O
OH
Carboxylic acid
STEP 2 A primary alcohol can be oxidized
either to an aldehyde or to a carboxylic acid,
depending on the reagents.
O
OH
STEP 3 Analyze reagents.
PCC is used to form the aldehyde. 
Chromic acid is used to form the 
carboxylic acid.
EXAMPLE 
OH
acetone
CrO3
H3O
+ ?
Try Problems 13.22, 13.23, 13.35e–f, 13.37, 13.48
13.8 CONVERTING FUNCTIONAL GROUPS
Br2, hν
 H3O
+
or
1) BH3 • THF
 2) H2O2, NaOH
 or
1) Hg(OAc)2
 2) NaBH4, NaOH
conc. H2SO4, heat
or
1) TsCl/pyr
2) NaOMe
HX
or
HBr, ROOR
NaOMe
or
t BuOK
Alkanes
C C
Alkenes
C C
Alkynes
C C
Alcohols
C
OH
Alkyl
halides
C
Br
Ketones/
aldehydes
C
O
H2
Pt, Pd or Ni
H2SO4, H2O
HgSO4
or
1) R2BH
2) H2O2, NaOH
H2, Lindlar’s catalyst
or Na, NH3
1) Br2
2) xs NaNH2
3) H2O
1) LAH, 2) H2O
or NaBH4, MeOH
H2CrO4
or PCC, CH2Cl2
HX or SOCl2/py or PBr3 
or 1) TsCl/py, 2) NaX
NaOH (SN2)
or H2O (SN1)
Try Problems 13.24–13.26, 13.39, 13.48, 13.51
13.9 PROPOSING A SYNTHESIS
MORE TIPS Remember that the 
desired product should be the major 
product of your proposed synthesis.
Always think backwards (retrosynthetic 
analysis) as well as forwards and then 
try to bridge the gap.
Most synthesis problems will have multiple 
correct answers. Do not feel that you have 
to find the “one” correct answer.
STEP 1 Is there a
change in the
carbon skeleton?
Keep track of all
the C C bond-forming 
reactions that you
have learned 
until now. 
STEP 2 Is there a change 
in the functional groups?
The chart from the previous
SkillBuilder summarizes 
many of the important 
functional group 
interconversions that we
have seen. 
STEP 3 After proposing a 
synthesis, analyze your answer 
with the following two questions: 
 
 Is the regiochemical outcome
 of each step correct? 
 Is the stereochemical outcome
 of each step correct? 
Try Problems 13.28, 13.29, 13.37, 13.38, 13.40, 13.45, 13.52, 13.59