Initials: _______
Chemistry 634, Fall 2014
Final Exam
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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 12 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 12 pages before
you begin.
Name: __________________________________________________
Problem
Points
1
_____/60
2
_____/40
3
_____/115
4
_____/45
5
_____/40
TOTAL
_____/300
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Initials: _______
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Initials: _______
1. (60 points) Please provide the missing reagents, intermediates, and products. In
some cases, more than one step may be required. If stereocenters are formed, you do
not need to indicate stereochemistry of products/intermediates or of the chiral catalyst
(you do not need to show a specific ligand if one is required, just give the general
structure).
F
O
N
N
F
NH2
[Rh(cod)Cl]2
H2, MeOH
N
Me
F
N
F3C
Fe
Pt-Bu2
PPh2
Ar
TBSO
+
O
Me
Ar
OH
OH
Ar
Ar
20 mol %
(Ar = 4-F-3,5-Et2C6H2)
NMe2
Me
O
O
3
Initials: _______
(1 – continued)
Me
Me
Me
Me
92% ee
Me Me Me
Me
O
B O
O
Me3C
O
Br
N
SEM
cat. Pd(PPh3)4
PhMe, K3PO4
90 °C
PhB(OH)2
cat. NiCl2(PCy3)2
K3PO4, PhMe
110 °C
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Initials: _______
2. (40 points) Please provide the products of the following reactions. If no reaction is
expected, please state “no reaction.” Indicate the predicted stereochemistry when
appropriate.
1. PPh3, CBr4
2. BuLi (2 equiv); then MeC(O)Cl
O
CH3
Δ
CH3
O
+
H
Δ
O
OH
Ph
1. Cl
Me
Et
2. LDA, TBSCl, –78° C, THF
3. Δ
5
Initials: _______
3. (115 points) (a) In their recent synthesis of gracilioether F, the Brown group utilized
intermediate (±)-2, which can be synthesized from cyclopentadiene 1. Please propose a
synthesis of (±)-2 from 1.
Et
1
Et
(±)-2
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Initials: _______
(3 – continued)
(b) In key step in their synthesis, the Brown group transformed 2 to 4. What type of
reaction is this? Please classify this reaction as is appropriate for its reaction type.
O
Ph
Cl
Me
AlMe3, i-Pr2NEt
Et
O
Ph
Me
AlMe3
Et
H
(3)
O
Me
Et
(±)-2
Et
H
(±)-4
Ph
Type of Reaction: __________________________
Classification: _____________________________
(c) Please show why this reaction is allowed under thermal conditions.
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Initials: _______
(3 – continued)
(d) Using clearly drawn pictures, please rationalize the observed stereochemistry of
product 4.
(e) Please provide the missing reagents in the following sequence. In some cases, more
than one step may be required.
Et
H
Et
O
H
Me
Et
H
(±)-4
O
Et Me
Et
Ph
Et
Et
H
Ph
Et
H O
O
Et
H
Me
Et
H O
O
Et
H
CO2H
Ph
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Initials: _______
4. (45 points) (a) Please provide the product of the following transformation. Indicate
stereochemistry, if appropriate.
Et
1) B2H6
2) H2O2/NaOH
Me
(b) Using clearly drawn pictures, please rationalize your predicted stereochemistry.
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Initials: _______
5. (40 points) Please draw a reasonable arrow-pushing mechanism for the following
reaction.
Ac
N
O
N
O
CO2t-Bu S
Ac
N
hν
CCl4
Cl
CO2t-Bu
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Initials: _______
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Initials: _______
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