Download Don`t forget to study the generic functional groups and the common

ALCOHOLS & PHENOLS SOLUTIONS
Don’t forget to study the generic functional groups and the common alkyl groups (isobutyl, etc).
1.
IUPAC = I and common = c.
a)
d)
4-isopropyl-2-methylphenol
6-methyl-4-propyl-3-heptanol
(this is the longest chain containing
the -C and with the most branch
points)
e)
b)
phenylmethanol (I)
benzyl alcohol (c)
4-cyclopentyl-2,2-butanediol
f)
3-penten-2-ol
c)
(Z)-4-methyl-2-cyclohexen-1-ol
or
cis-4-methyl-2-cyclohexen-1-ol
g)
2-cyclopenten-1-ol
2. Draw structures of the following compounds:
a) glycerol
OH OH OH
d) hydroquinone
OH
CH2 CH CH2
(also glycerin or 1,2,3-propanetriol)
OH
e) -naphthol
b) m-cresol
OH
OH
CH3
c) resorcinol
f) allyl alcohol
OH
OH
CH2CH
CH2
OH
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ALCOHOLS & PHENOLS SOLUTIONS
3. Give IUPAC names and, where possible, common names for the following compounds.
a)
OH
d)
CH3
CH2
HO
3
4
CH CH2 CH CH3
1
2
CH3
(c) sec-butyl alcohol
(I) 2-butanol
CH3
3-(1-ethyl-3-methylbutyl)phenol
e)
b)
H3C
C
OH
CH3
Br
OH OH
(c) t-butyl alcohol
(c) 2-methyl-2-propanol
CH2CHCH2CH2CHCH3
5-bromo-1,2-hexanediol
f)
OH
OH
c)
OH
isobutyl alcohol (c)
2-methyl-1-propanol (I)
catechol (c)
1,2-dihydroxybenzene (I)
2-hydroxyphenol (I)
4. Draw structures of the following compounds
a) isoamyl alcohol
d) 2-ethyl-2-buten-1-ol
OH
HO
e) trans-2-ethyl-3-methyl-2-penten-1-ol
b) 1-cyclopentyl-1-phenyl-2-propanol
OH
HO
c) cis-2-iodocyclohexanol
f) (E)-1-chloro-1,2-cyclobutanediol
OH
Cl
I
OH
H
OH
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ALCOHOLS & PHENOLS SOLUTIONS
5. Note that this is a 3° alcohol.
a)
Br
HBr, H2O
SN1
OH
H2O
+
CH3
CH3
1-bromo-1-methylcyclohexane
b)
O- Na+
Na
Na metal is a very strong base.
It deprotonates alcohols.
1/2 H2
+
CH3
sodium 1-methylcyclohexoxide
c)
H2SO4
CH3
3° alcohols are readily
dehydrated by sulfuric
or phosphoric acids
and moderate heating
H2O
+
1-methylcyclopentene
d)
cold
Na2CrO4, H2SO4, H2O
e)
PBr3
NO REACTION
3° are only oxidized under severe
(hot) conditions with strong oxidants
Br
+
CH3
This is the same product as obtained with HBr
Again the mechanism is SN1 for 3° alcohols
PBr2OH
6. What Grignard and what carbonyl will react to produce the following. Draw structures of all
possible combinations.
O
O
C
CH3
+
CH3MgBr
OR
+
2 CH3MgBr
H3C
OH
C(CH3)2
C
CH3
MgBr
+
O
C
7. What hydride and what carbonyl will react to produce the following. Draw structures of all
possible combinations.
CH3
CH3
OH
C
CH2
CH3
CH3
O
C
C
H
CH3
CH3
CH3
+
NaBH4
CH3
O
C
C
OR
CH3
+
CH3
2 LiAlH4
CH3
O
C
C
OH
CH3
+
3 LiAlH4
Page 3
ALCOHOLS & PHENOLS SOLUTIONS
8. List the reagents needed for the following transformations
a)
CH3
CH2
CHBr
CH3
CH3
CH
CH
c)
CH
CH
CH3
CH3
CH2
CH3
CH(OH)
CH2
CH3
CH(OH)
CH3
CH3
CH2
KOH
H3PO4 + H2O
or
H2SO4 + H2O
b)
CH3
CH3
CHBr
CH3
Any strong base will cause
this 2° alkyl halide to
dehydrohalogenate via E2
1 Hg(CH3COO-)2, THF, H2O
or 2 NaBH4
Any of the standard reagents
used for hydration of alkenes
HBr or PBr3
Either reagent causes 2°
alcohols to undergo SN2.
O
d)
CH3
CH2
CH(OH)
CH3
CH3
CH2
C
PCC or Collins
CH3
or
KMnO4 or HNO3
Any mild or moderate oxidant
will oxidize a 2° alcohol to a ketone
e)
CH3
CH2
CH(OH)
f)
g)
CH3
CH3
CH2
CHCl
CH3
HCl or SOCl2
will convert alcohols
to alkyl chlorides
Only a rhodium catalyst
allows hydrogenation of
H2/Rh an aromatic ring at standard
pressure and temperature.
Carboxylic acids are not reduced
by hydrogen.
COOH
COOH
CH2OH
COOH
Only this reagent will reduce
1 LiAlH4
carboxylic acids but it does not
2 H2O reduce alkene/alkyne unsaturation
9. Number the following compounds in order of acidity, i.e., 1 = most acidic, 4 = least acidic
OH
OH
COOH
NO2
3
4
1
2
Carboxylic acids are more acidic than phenols. The nitro group is electron
withdrawing so it will help stabilize the negative phenoxide ion after
deprotonation, making it more acidic than phenol. Benzene has only non
polar C-H bonds, they are not acidic.
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ALCOHOLS & PHENOLS SOLUTIONS
10. The shortest routes are shown below. In some cases, other, longer synthetic routes are
possible.
a)
OH
CH2
CH2
OH
CH
H2O
Markovnikov
H2SO4 product
H2O
POCl3,
N
b)
CH2
POCl3,
CH
E2
CH2
CH2
OH
H2O
CH2OH
1 LiAlH4
2 H2O
KMnO4
N
O
or
CH2
CH
CH3
C
OH
hot KMnO4
OH
OH
c)
CH
C
CH3
CH3
CH3
Cr+6, H+
any oxidant
1 CH3MgBr
ether
O
C
+
2 H3O
CH3
Page 5
ALCOHOLS & PHENOLS SOLUTIONS
11. This one is tougher. Note the addition of the ethyl group. The only methods we’ve learned for adding
Carbon groups are 1) chain lengthening terminal alkynes, 2) FC alkylations/acylations to aromatics,
3) Grignards, organosodium and Gilman reactions. Obviously the first two don’t apply here, so look
for an opportunity to perform a Grignard rxn, i.e., synthesize a carbonyl to add the Grignard to:
OH
OH
CH2CH3
oxidize
Cr+6, H+
1 BH3, THF
2 NaOH, H2O2, pH8
1 CH3CH2MgBr, ether
+
2 H3O
O
antiMarkovnikov
addition
conc. H2SO4
CH2CH3

3°
Grignard reaction
dehydration
CH2CH3
OH
12. For the following reaction:
a) Write products for the reaction
b) Show the mechanism of the reaction
..
O
..
c) Calculate pKeq
..
O:
..
H
+
Na OH
-
Na+
+
H2O
pKb = -1.74
phenol
pKa = 9.9
sodium phenoxide
pKeq = pKa + pKb - 14 = (9.9 -1.74 - 14) = -5.8 (100% extent of reaction)
13. This 3° alcohol is undergoing an SN1 reaction. OH is a poor leaving group, but once protonated by a
strong acid, a better leaving group is formed (H2O).
CH3
H3C
C
..
O
..
H
H
..
Cl :
..
3°
CH3
SN1
CH3
H3C
C
H
+
O
..
H3C
C
Cl
CH3
H
H3C
H2O
C+
..
: ..
Cl :
Page 6
ALCOHOLS & PHENOLS SOLUTIONS
14. Remember to consider whether the substrate is 1°, 2°, or 3°
CH3
CH3
a)
KOH
Br
b)
H3C
CH2
CH
OH
+
C
PCC is a mild oxidant, oxidizing
1° alcohols to aldehydes
H
H3C
H3C
c)
This 3° halide undergoes E2
rxn. with strong bases
H2O
O
H3C
PCC in CH2Cl2
CH
KBr
+
O
OH
Jones Reagent
CH
2° alcohols are oxidized
to ketones by mild or
moderately strong oxidants
CH3
C
CH3
O
d)
1. Cl
CH3
H3C
S
CH3
O
C
CH2
C
H3C
OH
O
CH3
CH3
LiAlH4
then
H3O+
2.
HO
S
CH3
O
H
H
+
Tosyl chloride converts the OH group to a good
leaving group, which is then displaced by Hydride
in an SN2 reaction.
e)
Na
OH
2°
f)
O- Na+
+
Br
+
PBr3
OH
POCl3
CH3CH2CH2CH2OH
g)
CH3CH2CH
CH2
PBr2OH
H3C
SOCl2
CH
CH2
and pyridine acts as a strong bulky base forcing
an E2 dehydration reaction even in 1° alcohols.
H3C
i)
H3C
CH
OH
HCl
CH
C
CH2Cl
SO2 H3C
O
OH
O
CH3
1 LiAlH4
2 H2O
CH2
CH
Like HBr, this reagent converts alcohols
to alkyl bromides. The mechanism is SN2
POCl3 converts to OH group to a better leaving group
+ H2O
N:
h)
CH2
Very strong bases like Na metal
1/2 H2 deprotonate weakly acidic protons
in water and alchols
CH2
Thionyl chloride coverts all alcohols to
alky halides. The OH group is converted
to a good leaving group. This 1° alcohol
reacts via an SN2 reaction
LiAlH4 reduces carboxylic acids and
esters to 1° alcohols but it does not
reduce C to C unsaturation.
Page 7
ALCOHOLS & PHENOLS SOLUTIONS
15. Draw the structures of a Grignard and a carbonyl compound that can be used to synthesize
the following alcohols. Show all possible combinations.
Also draw the structures of any carbonyl compounds that can be reduced by a LiAlH4 to
prepare these compounds
O
a)
O
OH
C
MgBr
C
2 CH3CH2MgBr
+
OR
CH3CH2
C
CH2CH3
+
CH2CH3
O
CH2CH3
C
CH2CH3
O
b)
OH
C
+
CH3CH2MgBr
O
+
OR
C
2 LiAlH4
C
OH
+
3 LiAlH4
H
H
O
O
+
H
C
NaBH4
C
H
H
+
MgBr
16. Write equations to show how the following transformations can be carried out. More than
one step may be required. Show all reagents and the products of each step, but do not
show any transition states. Mechanisms are not required
a)
OH
OH
CH3
Cr+6, H+
1 CH3MgBr
O
b)
+
2 H3O
OH
O
CH3
CH3
Na
CH2CH3
or
CH3CH2Cl
Na+NH2O- Na+
SN2
CH3
O
c)
CH2CH2CH3
CH3CH2CH2I
H2SO4
SO3
300° C
1 NaOH
SO3H
+
2 H3O
SN2
OH
NaOH
O- Na+
acid/base
Page 8
ALCOHOLS & PHENOLS SOLUTIONS
:O..
17. .
C(CH3)3
H+HSO4-
H
CH
Zaitsev product
(CH3)2C
CH3
C(CH3)2
E1
CH3
+
H
:O
C(CH3)3
CH
C
H3C
H
C
CH3
CH3 H
CH3
CH3
H3C
C
+
C
CH3 H
HSO4-
3°
CH3
rearrangement via
methide shift
2°
18. Draw the structure(s) of all reagents which would give the following alcohol when reduced
with LiAlH4
(CH3)2CHCH2OH
(CH3)2CHC
O
O
O
H
(CH3)2CHC
or
(CH3)2CHC
or
OR
OH
19. Draw the structures of all sets of reagents that would give the following alcohol when
reduced with a Grignard reagent. Show Grignards as well as other reagents.
O
OH
CH3CH2CCH2CH3
CH3CH2CCH2CH3
+
CH3
O
O
CH3CH2CCH3
or
2 CH3CH2MgBr
CH3CH2MgBr
+
CH3MgBr
+
CH3COR
or
20. Draw the formulas or structures of the products of the following reactions ...
a)
H3C
H3C
2°
H3C
POCl3
POCl3 converts the OH group to
a good leaving group. Pyridine acts
as a strong bulky base causing E2
dehydration to the alkene.
Two products form.
+
OH
N
b)
H3C
H3C
2°
PBr3
Br
OH
PBr2OH
+
PBr3 works like HBr to convert
alcohols to halides.
SN2
H3C
c)
d)
H3C
cold KMnO4
aqueous
2°
O
OH
H3C
hot concentrated
HNO3
2° alcohols are normally oxidized to
ketone except under severe conditions
in which case they are oxized to
carboxylic acids and cleaved.
O
H3C
O
C
OH
C
Cleavage occurs on either side of the -carbon
H3C
OH
OH
OH
C
+
C
OH
O
O
Page 9
ALCOHOLS & PHENOLS SOLUTIONS
H3C
21.
3-methylcyclohexanol
potassium 3-methylcyclohexoxide
H3C
K
O- K+
OH
+
1/2 H2
K (like Na and Li) is a very strong base and deprotonates
the weakly acidic alcohol in an acid/base reaction.
This is a rapid lab test for identifying alcohols; H2 gas is evolved.
22. Remember to think backwards from the product as well as forwards from the reagent.
a)
CH2CH2OH
CH2OH
KMnO4
H3O+
1 LiAlH4
2 H2O
O
COH
b)
Br
1°
OH
CH2
CH3
H2SO4
H2O
KOH
SN2
Markovnikov
product
OH
POCl3,
CH2
CH2
E2
N
1°
OH
c)
SO3
H2SO4
CH2Br
(PhCO2)2
NBS
SO3H
OH
1 NaOH, 300°C
+
2 H3O
OH
AlCl3
CH3
CH3Cl
d)
H3C
O
H3C
CH
C
C
OCH3
C
H3C
H3C
2 equiv.
1 C6H5MgBr
+
2 H3O
OH
H3C
CH
C
POCl3, N
or
H2SO4 
H3C
Page 10