Download chm238f02.exam2

CHM238-01
103- points
EXAM 2
October 14, 2002
Name:
1. (6 pts) Name the following alcohols:
NO 2
OH
OH
OH
H3C
O 2N
OH
CH3
H3C
2. (15 pts) The most effective way to make an alkoxide anion is to react an alcohol with metallic sodium producing hydrogen gas.
(a) Write a balanced reaction for the formation of methoxide from methanol.
(b) Given pKas: CH3OH = 45; CH3OH = 16; H2 = 38; H2O = 16; PhOH = 10:
Predict the direction and Keq of the reaction above.
(c) Would NaOH be a good enough base to turn methanol completely into methoxide? Write the reaction. Predict the direction
and Keq of the reaction.
(d) Which is more acidic, phenol or methanol? Why? By how many times?
3. (12 pts) Write the name or acronym of the dominant reaction mechanism for the reactions below. If you don’t believe the
reaction would really occur as written, write the abbreviation MI (Mission IMPOSSIBLE).
Br
NaNH 2/NH 3
NH2
(a)
CH3
HNO 3/H2SO4
CH3
CH3
+
NO 2
O 2N
(b)
Br
NaOCH 3/CH3OH
O
CH3
(c)
NO 2
NO 2
OH
O
CH3
LAH
CH3
(d)
H3C
H3C
OH concentrated aqueous acid
+
CH2
H2O
CH3
(e)
OH
OH
Jones Reagent
O
(f)
4. (12 pts) Choose the best set of reagents to carry out the following conversions to the highest yield form the choices given.
Write the letter of the best choice in the blank.
O
A.
D.
1. HNO3, H2SO4
2. Br2, FeBr3
3. NaOH (aq)
1. (CH3)2CHCH2CH2Cl, AlCl3
2. HNO3, H2SO4
B.
1. Br2, FeBr3
2. CH3Cl, AlCl3
3. KMnO4, H3O+
1. Br2, FeBr3
2. HNO3, H2SO4
3. NaOH(aq)
E.
O
G.
J.
Cl , AlCl3
1.
2. H2, Pt
3. HNO3, H2SO4
1. Br2, FeBr3
2. NaNH2, NH3
H.
Cl , AlCl3
1.
2. H2, Pt
3. Br2, FeBr3
1. Br2, FeBr3
2. NaNH2, NH3
3. HNO3, H2SO4
K.
(a)
O
Br
OH
(b)
OH
(d)
F.
O
Br
(c)
C.
O2N
O2N
Cl , AlCl3
1.
2 Br2, FeBr3
3. H2, Pt
1. CH3Cl, AlCl3
2. KMnO4, H3O+
3. Br2, FeBr3
O
I.
L.
Cl , AlCl3
1.
2 HNO3, H2SO4
3. H2, Pt
1. NaOH (aq), 3500C, high P
2. Br2, FeBr3
3. HNO3, H2SO4
5. (12 pts) Preparation of alcohols by Grignard reagents reacted with C=O compounds is very important.
(a) If the Grignard reagent were phenyl Grignard, PhMgBr, draw the C=O compound would be the best one to use in order to
make the following alcohols If it doesn’t work, write NR.
(b) If the Grignard were, ethyl Grignard, EtMgBr, draw the C=O compound would be the best one to use in order to make the
following alcohols. If it doesn’t work, write, NR.
a = Carbonyl compound to use with Phenyl Grignard
b = Carbonyl compound to use with Ethyl Grignard
HO
CH3
CH3
a=
b=
a=
b=
OH
CH3
6. (18 pts) Provide the major organic products for the following reactions. If no reaction occurs, write NR. Do 6 out of 8. Cross
out the one you don’t want graded or graded in order.
H3C
+
Cl
H3C
(a)
H3C
NaOH (aq) 350C, high P
Br
(b)
H2SO4
O
+
CrO 3, H2SO4 (excess)
HO
OH
(d) H3C
PCC (excess)
HO
OH
(e) H3C
O
CH 2Cl 2
1. NaBH 4
O
CH3
H3C
O
O
(g)
2. acid workup
1. LAH
O
CH3
H3C
HNO 3
CH3
NH
(c)
(f)
AlCl 3
O
2. acid workup
H3C
CH3
NBS, FRI
(h)
7. (10 pts) Starting from benzene and any other organic or inorganic compounds, show routes to the following products. You will
need at least two steps. Assume that you can separate o and p.
OH
O
O2N
OH
8. (10 pts) One problem with trying to react the following alcohol with HBr in order to get the alkyl bromide is the rearrangement
that occurs under acidic conditions. Consider the situation shown below.
(a) Provide arrows and necessary lone pairs to complete the reaction flow for the unexpected alcohol substitution reaction:
H
H
OH
H
Br
CH3
CH3
H3C
H3C
H
H3C
H3C
H3C
H
OH 2
H3C
Br-
CH3
Br-
+
H2O
H3C
H3C
CH3
+
H2O
H3C
BrH3C
CH3
Br
(b) What is the name of the starting alcohol?
(c) Which reagent(s) would you use if you wanted to substitute the alcohol with bromide in the same position and with inversion
of configuration, without any rearrangement.
(d) This type of rearrangement can occur when trying to hydrate an alkene in acid. If we add water and acid (acid catalyzed
hydration) to the 3-Methyl-1-butene, the main product is 2-methyl-2-butanol.
HO
H3C
CH2
CH3
H2 O
H3C
CH3
H
+
CH3
Which reagents would you use to make the starting alcohol in a above from 3-Methyl-1-butene, without rearrangement?
9.
(10 pts) Identify the organic compound that matches most closely to the spectra on the page. Draw the structure and then
draw lines from the H’s to the peaks in the NMR. Identify any peaks you can in the IR.