ORGANIC CHEMISTRY II
Problem Set Chapter 18
1.
Name the following compounds using IUPAC nomenclature.
CH3
CH3 CHCH3 OCH2CH2CH2CH3
1-(2-methylpropoxy)butane
CH3
CH3CH2 CHCH2 O
OCH2 CH3
Br
1-Bromo-2-ethoxy-4-(2methylbutoxy(benzene
O
CH3CH2CHCH2
1,2-epoxybutane
2.
Devise a synthesis scheme for the following conversions. If more than one
reaction is required,
show the major product for each reaction used.
CH3CH CH2
CH3CHCH2OCH3
OH
m-CPBA
epoxidation CH 2Cl 2
CH 3O - Na+ SN2 at less
hindered epoxide
CH 3OH
w / peracid
carbon
O
CH 3CH
CH 2
CH3CH CH2
CH3CHCH2OH
OCH3
m-CPBA
epoxidation CH 2Cl 2
H+
Protonation of epoxide
CH 3OH oxygen and SN1 at more
w / peracid
substituted epoxide
carbon
O
CH 3CH
CH3CH CH2
CH 2
CH3CH2CH2OCH3
HBr
peroxides
Br
CH 3CH 2
CH 2
CH 3O - Na+
CH 3OH
SN2 Substitution
on 1˚ alkyl halide
CH3CH CH2
CH3CH(OH)CH2OH
m-CPBA
epoxidation CH 2Cl 2
HO - Na+
H2O
OR
H+ , H20
w / peracid
O
CH 3CH
3.
CH 2
Show how you would accomplish the following transformations.
OH
-
CH 3CH 2O Na
+
O
CH 3CH 2CH 2CHCH2
CH 3CH 2CH 2CHCH2OCH2CH 3
H+
CH 3CH 2OH
OCH2CH 3
CH 3CH 2CH 2CHCH2OH
CH 3
OH
CH 3
C CH 3
CH 3CH 2CHCH 2CH 3
O
CH 3CH 2CHCH 2CH 3
+
H
Heat
1) Hg(OAc)2
(CH 3)3COH
2) NaBH 4
CH 3CH 2
CHCH 3
Need to add two carbons
CH 3CH 2CH 2Br
CH 3CH 2CH 2CH 2CH 2OH
O
Mg
ether
1) CH 2
CH 2
2) H2O
CH 3CH 2CH 2MgBr
4. Use a Williamson synthesis to form the compound at below.
CH 3
CH 3C
O CH 2CH 2CH 3
CH 3
CH 3
CH 3 C O - Na+
CH 3
+ CH 3CH 2CH 2Br
5.
Show the reaction of the above product with hot, concentrated HI.
CH 3
CH 3C
CH 3
HI, heat
CH 3 C I + CH 3CH 2CH 2OH
CH 3
O CH 2CH 2CH 3
CH 3
Protonation of the ether oxygen followed by loss of CH 3CH3CH2OH,
results in a 3˚ carbocation, which then reacts with an iodide anion.
6.
Show the product from the reaction of sec-butyl methyl ether with hot
concentrated HI in excess.
CH 3
H
C O CH 3
CH 2CH 3
HI, heat
CH 3
H
C OH + CH 3I
CH 2CH 3
Protonation of the ether oxygen results in the conversion of the oxy
linkage into a good leaving group. SN2 substitution on the methy
group by the iodide anion displaces 2-butanol from the molecule
7.
Show a reaction schematic which would accomplish the following
conversions. SHOW THE MAJOR PRODUCT FOR EACH REACTION
USED IN THE SCHEMATIC.
a. phenol → ethoxybenzene
1) NaH
OH
OCH 2CH 3
2) CH3CH 2-I
b. propene → diisopropyl ether
H3C
H
C
CH 2
NaBH 4
Hg(OAc)2
(CH 3)2CH-OH
H3C
CH O
H3C
CH 3
CH
CH 3
c. ethene → 1-butanol
CH 2 CH 2
m-CPBA
O
CH 2 CH 2
CH 3CH 2MgBr
H2O
CH 3CH 2CH 2CH 2OH
d. toluene → ethyl benzyl ether
CH 2Br
CH 3
NBS
peroxides
CH 2OCH 2CH 3
NaOCH 2CH 3
8.
Show the two reagents needed to prepare the following ethers using the
Williamson synthesis.
a. CH3CH2CH3-O-CH(CH3)2
CH 3
CH O - Na+
CH 3
b.
+
CH3CH 2CH 2-Br
CH3CH2CH3-O-CH(CH3)2
CH2 O CH2CH3
SEE Problem 7d Above
9.
Show the reagents needed to prepare the following ether using
alkoxymecuration-demercuration.
CH2 O CH2CH3
CH 2 CH 2
Hg(OAc)2
CH2 O CH2CH3
NaBH 4
CH 2OH
10.
Show the complete mechanism for the reaction below.
a.
CH2 O CH2CH3
CH2 O CH2CH3
+
+
HI
CH2
H+ I-
+
O CH2CH3
H
- CH3CH2OH
CH2I
I
-
+
CH2
CH2
+
Resonance Stabilized Benzyl
cation
Br
OH
b.
NaOH
OH
Br
OH
Br
-
OH
OBr
H
H
H
H
H
O
Br
H
H
H
OH
H
This does not
have the correct
stereochemistry
to form an epoxide
O
+
c.
HBr
+
O
O
+
H
HBr
OH
H
H
Br -
Br