Initials: _______
Chemistry 634, Fall 2014
Midterm 1
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Closed note, closed book. No calculators allowed. You may use a molecular model
set.
Answers must be written in the spaces or boxes provided. Other markings will not be
considered.
Please initial each page at the top.
Points will only be awarded for clearly communicated answers.
There are 9 total pages to this exam. The last 2 pages were intentionally left blank
and may be used for scratch paper. Please be sure your copy has 9 pages before
you begin.
Name: __________________________________________________
Problem
Points
1
_____/30
2
_____/40
3
_____/30
4
_____/20
5
_____/40
6
_____/40
TOTAL
_____/200
1
Initials: _______
1. (30 points) Please provide the reagents needed for each of the following
transformations. In some cases, more than one step may be required.
OH
HO
OH
HO
O
O
O
BnO
O
O
H
H
Si(i-Pr)3
H
Si(i-Pr)3
H
Br
OMEM
OMEM
2
Initials: _______
2. (40 points) Please fill in the missing intermediates in the following synthesis.
HO
Me
Me
BnO
CO2Me
OTBS
(i-Pr)O2CN NCO2(i-Pr)
PPh3, MeCO2H
OH
H
HO
TIPSOTf
2,6-lutidine
K2CO3, MeOH
Me
Me
BnO
CO2Me
OTBS
H
OTIPS
AcO OAc
I OAc
O
H2, Pd/C
O
pyridine
HO
TMS
n-BuLi;
then ClCO2Me
Me
Me
CO2Me
OTBS
OTIPS
H
OCO2Me
TMS
3
Initials: _______
3. (30 points) Please provide formal oxidation state, d-electron count, and valence
electron count for the metal in each of the following transition metal complexes.
Complex
Mes N
Ru
Formal oxidation
state
d-electron count
Valence electron
count
N Mes
Cl
Cl
O
Me
Me
Co
OC
CO
Cl Au P(t-Bu)3
H
N
H
N
Mn
O
Cl
O
N Cl CO
Re
N Cl CO
4
Initials: _______
4. (20 points) Please draw a reasonable, arrow-pushing mechanism for the
following transformation. Note: This problem is from Grossman’s The Art of
Writing Reasonable Organic Reaction Mechanisms.
O
O
N
MeN
O
N
Me
N
O
NH
Br
CO2t-Bu (2 equiv)
K2CO3 (2 equiv)
N
MeN
O
CO2t-Bu
O
N
Me
N
N
CO2t-Bu
5
Initials: _______
5. (40 points) A) Please provide a detailed mechanism for the following reaction.
You do not need to show the generation of Pd(PPh3)n; you may start your
mechanism with Pd(PPh3)n.
O
O
"catalytic Pd(PPh3)n"
10 mol % Pd(OAc)2
40 mol % PPh3
I
O
NHCO2CH3
O
Ag2CO3, THF, 66 °C
(73%)
O
NHCO2CH3
O
O
O
O
O
B) Please draw a clear transition state model for the C–C bond formation that
rationalizes the observed diastereoselectivity.
6
Initials: _______
6. (40 points) Please propose a synthesis of 2 from aniline (1). In addition to aniline,
you may only use reagents containing 2 or fewer carbons as sources of carbon.
Me
O
NH2
1
aniline
N
Me
2
7
Initials: _______
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Initials: _______
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