ETHERS&THIOLS SOLUTIONS
Don’t forget to study the generic functional groups and the common alkyl groups (neopentyl, etc.)
1. Give the IUPAC (I) and where possible the common (c) names for the following:
a)
OCH3
e)
CH3
S
CH
CH3
(I) (isopropylthio)cyclopentane
(I) (1-methylethylthio)cyclopentane
(c) cyclopentyl isopropyl sulfide
4-methoxycyclohexene
b)
O
f)
H2C=CHCH2-O-CH=CH2
(c) allyl vinyl ether
oxetane
c)
g)
O
CH2CH3
2-ethylfuran
d)
SH
CH3
CH2
CH
OH
(I) 3-mercapto-2-methyl-1-propanol
(I) 2-methyl-3-thio-1-propanol
CH2 S
O
h)
(c) benzyl phenyl sulfide
(I) (phenylthio)toluene
(I) phenyl(phenylthio)methane
CH2
Br
3-bromopyran
2. Draw structures of the following:
a) isopropyl neohexyl ether
d) di(p-chlorophenyl) ether
Cl
O
b) tetrahydrothiophene
O
Cl
e) 1,3-(dimethylthio)benzene
S
CH3
S
S
c) 9-crown-3 ether
O
O
CH3
f) isobutyl mercaptan
SH
O
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ETHERS&THIOLS SOLUTIONS
3. Draw structures of the following
a) 2-mercaptobenzoic acid
h) thiopyran
COOH
S
SH
b) 2,2-diethoxybutane
i)
tetrahydrofuran
OCH2CH3
O
OCH2CH3
c) 3-(ethylthio)cyclopentene
j)
sec-butyl phenyl sulfide
S
SCH2CH3
d) isopropyl tert-butyl ether
k) t-amyl isohexyl ether
O
O
e) neopentyl mercaptan
l)
12-crown-4 ether
O
O
O
O
SH
f) p-methoxyanisole
OCH3
m) diphenyl sulfide
S
CH3O
g) ethyl m-tolyl ether
H3C
n) 2-pentanethiol
O
SH
CH2CH3
4. Give the IUPAC (I) and where possible the common (c) names for the following
a)
c)
O
2-methoxyoxetane
O
b)
O
CH3
O
d)
1,4-dioxane
oxirane
or
ethylene oxide
O
CH3SCH3
dimethyl sulfoxide
O
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ETHERS&THIOLS SOLUTIONS
5. Draw the full mechanism (using arrows) and write products of the Williamson Ether
synthesis with sodium methoxide and ethyl bromide. Name the type of mechanism and
name the product
.. - +
..: Na
CH3O
..
: Br
..
+
strong base
good Nu
CH2CH3
CH3OCH2CH3
SN2
1°
+
NaBr
methyl ethyl ether
or methoxyethane
6. Write equations, showing all reagents required to produce the following compounds using
Williamson type synthesis. Include the intermediate products (mechanism and transition
states not required). Hint: each one requires two steps.
a)
(1 of the reagents must contain an -OH group)
CH3
O
CH2
This is the only route.
CH
CH3
CH2 Br
H3C
Na+NH2CH
H3C
SN2
acid/base
H3C
OH
O- Na+
CH
2°
NH3
H3C
b)
(1 of the reagents must contain an -SH group)
CH3
S CH
Br
This is the only route
CH3
SN2
NaOH
SH
S- Na+
acid/base
c)
(1 of the reagents must contain an -OH group)
O CH2CH3
CH3CH2Br
SN2
NaOH
OH
acid/base
This is the only route
O- Na+
moderate base
good Nu
PAGE 3
ETHERS&THIOLS SOLUTIONS
7. Write the products of the following reactions. No mechanisms required
a)
Cl
O
O
C
O
OH
b)
Br
CH3CH2CH2O- Na+
+
+
strong base
good Nu
c)
C
1°
NaBr
CH3
CH2Br
+
O- Na
+
E2
2°
CH3
H3C
CH3CH2CH2OH
H3C
+
C
O
CH2
+
NaBr
CH3
CH3
Benzyl bromide cannot dehydrohalogenate
so E2 is not possible, only SN2
strong bulky base
good Nu
d)
cold H2O2
CH3CH2 S
O
then hot H2O2
CH3CH2SCH2CH3
CH3CH2SCH2CH3
CH2CH3
O
O
e)
O- Na+
1.
OH
O
CH2
CH2
CH2
2.
f)
O
CH2
O
H3O+
NaOH
H2O
OH
OH
show stereochemistry
of the product
g)
SH
NaOH
S- Na+
+
H2O
PAGE 4
ETHERS&THIOLS SOLUTIONS
8. Remember to think backwards as well as forwards.
a)
Br
2°
CH
OH
OCH2CH3
CH
CH2
CH3
1 Na+ -OCH2CH3
+
2 H3O
KOH
HBr
CH
Cl
O
O
C
CH2
OH
O
CH
CH3
CH3
b)
CH2 S
Cl
CH
CH2
2°
CH2
CH2
CH3
CH3
NBS
(PhCO2)2
CH3
SN2
CH2Br
CH2
Cl
SOCl2
CH3
S
or
CH2
SN2
CH2Br
product
above
1°
CH3
1 NaOH
CH3Cl
SN2
2°
Br
NaOH
S- Na+
SH
SN2
moderate base
v. good Nu
CH3
CH3
H2S
Na+HSmoderate base
v. good Nu
HC S- Na+
acid/base
CH2
CH3
c)
NaOH
HC SH
SN2
CH2
CH3
H3C
H3C
NaSH
CH
CH2S- Na+
acid/base
SN2
2°
HO CH
CH2SH NaOH
NaSH
1°
OR
CH3
2°
HO CH
CH3
SOCl2
CH
CH3
CH3Cl
AlCl3
CH2
acid/base
moderate base
v. good Nu
CH3Cl
NaOH
CH3SH
acid/base
CH3S- Na+
2°
moderate base
v. good Nu
Br
SN2
To above
product
PAGE 5
ETHERS&THIOLS SOLUTIONS
9. Write the products of the following reactions. No mechanisms required
O
a)
CH CH2
CH CH2
metachloroperoxybenzoic acid
(MCPBA)
b)
CH3O- Na+
H
HO
Note the antiaddition product
because the mechanism is SN2
O
H2O
OCH3
H
c)
NaOH
S- Na+
SH
+
H2O
acid/base
d)
O
H+
H2O2
CH3-S-CH3
O
H+
H2O2
CH3-S-CH3
cold
DMSO
Note that thiols are
moderately strong acids,
easily deprotonated by
strong bases
CH3-S-CH3
hot
O
dimethyl sulfone
10. Write equations showing how the following transformations can be carried out. No
mechanisms required but show all reagents and intermediate products formed. More than
one step may be necessary
a)
SH
CH3CH2CHCH3
CH3CH2CH=CH2
HCl
Markovnikov
addition
SN2
NaSH
Cl
CH3CH2CHCH3
2°
CH2
H2S
b)
1 NaOH
+
S
acid/base
-
Na HS
acid/base
SN2
SN2
CH2I
1°
CH2S- Na+
CH2SH
CH2I
1°
CH2
NaOH
PAGE 6