basic chemistry review examccc.chem.pitt.edu/wipf/courses//2320_07_files/sophomore_selftest.pdf ·...
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Dr. Peter Wipf Chemistry 2320 – Sophomore Organic Chemistry Self-Test 1/1/07
Name________________________________
Basic Chemistry Review Exam
CHEM 2320 Page 2 A. (40 points) Provide products for the following reactions:
a)
CH3
OCH3
NO2
SO3, H2SO4
b)
1. HBr
2. Me2NH
c)
O200 °C
d)
HgCl2, H2O
CHEM 2320 Page 3 B. (30 points) Order the hydrogens HA, HB, HC etc according to increasing pKa.
OHB
HC
O
N
HDHA
HE
HFO
C. (30 points) While watching an episode of “The Brady Bunch” you get a phone call from a class mate who has been under a lot of pressure recently studying for OChem 2. He would like you to draw for him the structures of a naturally occurring (S)- and a naturally occuring (R)-amino acid in the extended conformations that clearly show the configurations at the alpha-carbons. Of course you are happy to help him out. Also list the common names and the 3-letter abbreviations of the amino acids you select.
CHEM 2320 Page 4 D. (30 points) Propose a detailed stereoselective synthetic approach toward the following compound starting from cyclohexanone and using reagents with 6 or fewer carbon atoms. Mechanisms are not required.
O
H
CHEM 2320 Page 5
E. (50 points) Propose a detailed mechanism for the following process (describe electron movements with reaction arrows). What is the name of this reaction? Also name key intermediates and the product.
CONH2 Br2, NaOH NH2
H2O
CHEM 2320 Page 6
F. (30 points) Propose a synthesis of the following compound from organic precursors not exceeding five carbon atoms. Clearly indicate the reagents that you will use to effect the transformations. Mechanisms are not required.
EtN
O
CO2Me
NEt O
CO2Me
CHEM 2320 Page 7 G. (50 points) ) What reagents would accomplish the following transformations (more than one might be needed)? a)
OMe
O
H
O
b)
NHMe
O
NHMe
c)
S
S
H
H
d)
HO
OH
e)
H
O OH
O
CHEM 2320 Page 8 f)
O OH
g) O O
h) O
i)
H2N CHC
CH3
OHN CHC
CH2
OHN CHC
CH2
OH
O
OH
HN CHC
CH3
OH
OO2N
NO2
+
H2N CHC
CH2
OH
O
H2N CHC
CH2
OH
O
OH
j) HO OH HO O
CHEM 2320 Page 9 H. (50 points) Predict the product(s) for the following transformations. Indicate stereochemistry where appropriate. a)
Br
KNH2, NH3
b)
NH2
NMe2
1. NaNO2, H2SO4
2.
c)
1. SOCl2
2. NH3
3. Br2, NaOH
4. H3O+
OH
O
d)
Me
N
H
Et
H+
+
O
H
H e)
HO
O
COOMeOH
catalytic H2SO4
CHEM 2320 Page 10 f)
PhSH, THF
NO2Br
Br
g)
+ O
O
O
1. AlCl3
2. Zn (Hg), HCl3. PCl54. AlCl3
h)
+ O
O
O
toluene, 50 °C
i)
O
O
MeNH2
j)
O
Ph
!
CHEM 2320 Page 11 I. (30 points) Suggest three different syntheses of cyclopentanecarboxylic acid. Each route should utilize one of the following reagents. Then use any number of steps and any other reagents needed. a)
Br
b)
BrBr
c)
O
CHEM 2320 Page 12 J. (60 points) The following sequence follows a strategy that complements Fischer’s proof of glucose. Fill in the missing reagents and structures (a) through (g). Use Fischer projections for all open-chain structures. Follow the hints in the parentheses.
D-Glucose
(a)
(b)
!-methyl-D-glucoside
O2, Pt
(a special reaction that oxidizes only the primary hydroxy group at C-6 into a carboxylic group)
H+, H2O
(c) (d)
D-glucuronic acid(write open-chain
form only)
CHEM 2320 Page 13
NaBH4
(e)
gulonic acid(write open-chain
form only)
!
-H2O
(f)
gulonolactone
Na/Hg
(g)
(write both pyran as well as open-chain form)
CHEM 2320 Page 14 K. (50 points) Provide the major products for the following reactions:
a)
OH
85% H3PO4
80 °C
b)
MeI
1. Mg, Et2O
2. CH3CHO
3. H3O+
c)
CH3
H Br
CH3
HCH3O
1. KI, acetone2. NaCN
d)
1. BuLi
2. HCHO
e)
NaBH4, CH3CH2OH
H
HO
CHEM 2320 Page 15 L. (30 points) Predict the major products for the following transformation. Draw all appropriate chair-chair intermediates to clearly illustrate your choice of the configuration of the intermediates and the product(s). Answers that do not provide a logical rationale for the choice of product or that lack stereochemical details will not receive partial credit.
Br2
H
H
CHEM 2320 Page 16 M. (40 points) Draw the most stable conformation of cis-1-methyl-2-phenylcyclohexane and calculate the relative energy of all possible chair conformers. What ratio of the conformers would you expect based on these energy values?
CHEM 2320 Page 17 N. (30 points) Assign all stereocenters in the following natural product:
O
O
O O
O
H
MeO O
wortmannin
Ac
CHEM 2320 Page 18 O. (40 points) Provide a detailed mechanism for the dissolving metal reduction of alkynes. Use arrows to indicate electron movement and name all important intermediates according to their characteristic electron count.
CHEM 2320 Page 19 P. (30 points) Provide a complete mechanism for the following reaction. What is the name of the product?
1. B2H6, THF
2. NaOH, H2O2, H2O
CHEM 2320 Page 20 Q. (50 points) ) What reagents would accomplish the following transformations (more than one might be needed)? a)
Br
Br
b)
CHO
O
c)
N N I
d)
OH
OH
e) OH
CH2D
CHEM 2320 Page 21 f)
OH
Br
g) OH
CH2ONa
h)
H
i)
j) O
CHEM 2320 Page 22 R. (40 points) What is the major intermolecular force that connects the following molecules? Indicate the structural orientiation of an ensemble of 3 (three) of these molecules in the gas phase. Is there any preferred, regular orientation? Provide clear, short answers; if you list more than one force, or if the drawings are ambiguous, or if the structures are incorrect, no partial credit will be given. a) Acetic acid b) Carbon tetrachloride c) Acetone d) N-Methyl acetamide
CHEM 2320 Page 23 S. (30 points) Suggest three different syntheses of 2-methyl-2-hexanol. Each route should utilize one of the following reactants. Then use any number of steps and reagents needed. a)
O
b)
O
c)
O
O
CHEM 2320 Page 24 T. (60 points) Suggest a structure for a compound X, C4H8O, that fits the following spectra. Assign all signals in 1H and 13C NMR, as well as one peak in the IR spectrum (if you assign signals or peaks incorrectly, or if there are incomplete assignments in the NMRs, there won’t be any partial credit for the correct ones).
CHEM 2320 Page 25
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