Chem 331, Exam 2. November 1, 2002
NAME
1) Deduce the structures of B and C. Give the correct IUPAC names of A and C. You do not
need to provide mechanisms. (25 points).
NH2
1) excess CH3I
2) Ag2O
∆
B
C11H27NO
C8H 16
A
(2S,5R)-5-methyl-2-heptanamine
write the IUPAC name of A here
C
(5R)-5-methyl-1-heptene
write the IUPAC name of C here
+
NMe3
OH–
draw the structure of C here
draw the structure of B here
2) For each pair, indicate if the compounds are enantiomers, diastereomers, or meso (10 pts each).
a)
S
R
Cl
Br
Cl R
R Br
Diastereomers
b)
HO
HO
R
R
H
H
S
OH
S
OH
Br
Enantiomers
Br
Chem 331, Exam 2. November 1, 2002
NAME
3) Circle the correct product. Give a detailed mechanism (with attention to stereochemical details) that explains
your choice. (30 points)
OH
OH
1) NaOH
O
Br
2) H+
O
O
OH
HO
O
HO
Br
O
O
OH
OH
HO
HO
OH
–O
Br
O
O
Br
HO
H O
–O OH
OH
O
O
O
Br
Br
–O
O
Br
O
–OH
H+
S OH
S
HO
HO
Br
O
HO
Br
O
Chem 331, Exam 2. November 1, 2002
NAME
4) Circle the correct product. Give a detailed mechanism (with attention to stereochemical details) that explains
your choice. (30 points).
H
R
1) TsCl,
H 3C
OH
H 3C
O S H
O
O
N
2) NaOH
O
O
O
H 3C
H 3C
O
H
R
S
OH
H
O
Step 1
O
O
O
H 3C
H 3C
O
H R S
H 3C
O
O
H
–
TsO
O
H O
+
HN
O
S Cl
O
+
N
HN
Cl–
:
Step 2
O–
O
H 3C
H 3C
O
O
OH
H 3C
R S
–
TsO
OH
TsO
TsO
R S
O–
O
S S
5) Circle the correct product. Give a detailed mechanism (with attention to stereochemical details) that explains
your choice. (30 points). Substantial points will be deducted if you do not draw an accurate 3-D representation of
the trans-decalin framework (i.e. you must draw the chairs)
Br
Br
Br
H
Br
Br
Br
H
Br
H
H
Breq
H
H
H
Br
H
Breq
H
H
H
Brax
H
Breq
Br
H
LDA
H
H
H
Breq
H
–N
The representation of trans decalin is above, and since trans decalin cannot ring flip, there is only one
axial bromine. This is the only one that can undergo anti-periplanar E2 elimination.
6) Deduce the structure of D, and draw a detailed arrow pushing mechanism for its formation. (30 pts)
MeOH
O
O
:
1
H NMR:
D
H+
13
2.08 (s, 3H)
2.58, (d, 2H, J=5.6 Hz)
3.27, (s, 6H)
4.65, (t, 1H, J=5.6 Hz)
:
C6H 12O 3
205.2 (s)
101.5 (d)
53.8 (q, 2 carbons)
47.3 (t)
31.0 (q)
:
H+
C NMR:
:
O
H+
O
OMe
+
O
H
O
O
OMe
:O
H
:
+ H
MeO
H
:
:
MeOH
MeOH
O
:
: OMe
+
O H
H
H
OCH3
O
MeOH
:
D
:
OCH3
: OMe
+
O Me
H
O
+
OMe
:
O
MeOH
:
:
The NMR data
tells us that the
aldehyde has
reacted but not
the ketone
O H
H
7) Provide a detailed arrow pushing mechanism.
OTs
H
+
catalytic H
CH3
H 2O
∆
H
CH3
H
H
H
H
OTs
+
H
alkyl shift
+
CH3
H
CH3
CH3
H
H
H
:
:O
H
H
H
H
CH3
H
+
CH3
H