Transcribed Text
Do the following assignment after you have finished working on Unit 8.
When you are satisfied with your answers, send the completed assignment
to your tutor for grading using the assignment drop box.
1. Provide a complete IUPAC name for each of the following compounds.
Assign stereochemistry (E/Z) where appropriate.
a. Me
Et Et
Me
b.
✧
✧❜
❜❜❜✧
✧❜
❜✧
✧
✧
✧✧
✧
✧
✧
✧
✧
c.
✧
✧❜
❜
✧
✧
❜
❜
✧
✧❜
❜
❜
❜
❜
❜
✧
✧❜
❜✧
✧
2. Provide chemical structures for each of the following compounds.
a. (2Z,5E)-2,5-octadiene
b. 1-(1-propynyl)cyclohexene
c. 2,2,3-trimethylpentane
3. Using either 1-hexene or trans-2-hexene as the starting material, describe
how you could prepare the following compounds using one or more
chemical steps. Make sure you choose the best starting material for each
synthesis.
a.
OH
b.
Br
c.
OH
Br
d. ✧
✧❜
❜✧
✧❜
❜❜❜
e.
O
4. Construct a potential energy diagram for the rotation about the C2 C3
bond of 2,2-dibromobutane (shown below). Be sure to consider the
relative energies of all staggered and eclipsed conformations in your
analysis.
H3C
CH3
Br Br
2,2-dibromobutane
5. Devise a multi-step synthesis of butanoic acid and hexanoic acid from
bromopentane.
Hint: The simplest solution generates both products at the same time in
the final step.
✧
✧❜
❜✧
✧
O
❜❜
OH ✧
✧❜
❜✧
✧❜
❜✧
✧
O
❜❜
OH ✧
✧❜
❜✧
✧❜
❜✧✧Br
butanoic acid hexanoic acid 1-bromopentane
6. Consider a hypothetical equilibrium that exists between compounds A
and B at room temperature (298 K). The G‡ for the forward reaction
(conversion of A to B) is 22 KJ/mol. Likewise, G‡ for the reverse
process has been determined to be 34 KJ/mol.
a. Calculate G◦ for the forward reaction and construct a potential
energy diagram for the conversion of A to B. Be sure to place the
transition state in accordance with the Hammond Postulate.
b. A flask containing a mixture of A and B at equilibrium was
discovered, and the concentration of A at room temperature was
determined experimentally to be 3.1× 10−2 mol/L. What is the
concentration of B?
7. Compound A (C12H18), upon treatment with H2 gas in the presence of
Lindlar’s catalyst, furnished compound B (C12H20) as the only product.
Compound B was then treated first with ozone and then with zinc dust
to yield the two compounds shown below in equal amounts. Provide
structures for A and B, being careful to show any relevant
stereochemistry. As well, be sure to explain your reasoning.
✧
✧
O
❜
❜
H
✧✧
O
❜
❜✧
✧
O
❜❜
H
8. Provide synthetic pathways for the following transformations. Be sure to
include the structure of any organic intermediates.
a. Prepare
Pr Pr
from ✧
✧❜
❜✧
✧❜❜
❜❜
Br
✧
✧❜
❜✧
✧
b. Prepare ✧
✧❜
OH
❜✧
✧ from ✧
✧❜
❜✧
✧❜❜
OH
Do the following assignment after you have finished working on Unit 16.
When you are satisfied with your answers, send the completed assignment
to your tutor for grading using the assignment drop box.
1. Provide a complete IUPAC name for each of the following compounds.
Assign stereochemistry (E/Z) and/or (R/S) where appropriate.
a.
Cl I
Br
b.
✧
✧
✧✧
Cl
❜
❜✧
✧
✧
✧
❜
❜❜❜✧
✧
Cl
c. I H
2. Starting with butane, show, using chemical equations, how you could
prepare:
a. 2-bromobutane
b. 1-bromobutane
Note: For the following targets, you may also choose to begin with
either 2-bromobutane or the 1-bromobutane as prepared above
without repeatedly showing how you made these two compounds. Be
sure to choose the best starting material for each job!
c. 1-butene
d.
✧
✧❜
❜✧✧D
e. 3-methylheptane
f. 5-methyl-3-heptyne
3. Show, using chemical equations, how you would prepare each of the
following compounds from benzene:
a. phenol
b. o-ethyltoluene
c. 3-chloroaniline
d. p-nitrobenzoic acid
4. Sketch the expected 1H NMR spectrum for the following compound,
doing your best to estimate and represent the chemical shift of each
proton, as well as the anticipated integrations and splitting patterns.
✧
✧❜
❜❜❜✧✧O❜❜✧
✧
✧
✧
✧ ✧
❜
✧❜
✧
✧
✧✧
✧
✧
✧
p-ethoxyphenylacetylene
5. For each of the following sets of reaction conditions, identify which
mechanism or mechanisms you expect to dominate: SNl, SN2, El, or E2.
Draw the major product or products you would expect to isolate in
each case.
a. Ph
✧✧❜
❜✧✧OTos H2O
GGGGGGGGGA
b.
❜
❜✧
✧❜
❜✧✧Cl KOH
GGGGGGGGGA
EtOH
c.
✧
✧❜
❜❜❜✧
✧❜
❜✧✧Br
✧
✧
✧ ✧
❜
❜
NaSCH3
GGGGGGGGGGGGGA
DMF
6. Compound A is a clear, colourless liquid with a molecular formula of
C7H10. Upon treatment of A with H2 gas in the presence of Pd on carbon,
a single product B (C7H14) is obtained. Compound A has a lmax at
232 nm in its UV spectrum but will not react with any dienophile in a
Diels-Alder fashion. Provide a structure for Compound A, and explain
how you arrived at your decision.
7. Identify which of the following compounds is most nucleophilic and
which is most electrophilic, and provide an explanation for your
decisions.
✧✧✧
✧❜
❜✭✭✭
✭ or
❜
❜✭✭✭✭
❤❤ ✧❤❤
✧
8. For the following pairs of compounds, explain how the listed
spectroscopic method or methods could be used to distinguish between
the compounds.
a. Use mass spectrometry to distinguish between:
O
and
O
2-heptanone 3-heptanone
b. Use 1H NMR spectroscopy to distinguish between:
O
and
O
H
2-heptanone heptanal
c. Use IR spectroscopy and UV spectroscopy to distinguish between:
✧
✧❜
❜❜❜✧
O
✧❜
❜✧
✧
✧✧✧
❜✧
❜
and ✧
✧❜
❜✧
O
✧❜
❜✧
✧
✧
❜✧
❜
ethyl phenyl ketone ethyl 5-cyclohexenyl ketone
d. Use IR spectroscopy and UV spectroscopy to distinguish between:
✧
✧❜❜
❜❜✧
✧
✧✧✧❜
❜✧ ❜
❜
and
✧
✧❜❜
❜❜✧
✧
✧❜ ✧✧✧
✧ ❜✧
o-xylene p-xylene
9. In an effort to identify it, an unknown compound, U, was subjected to
extensive spectroscopic analysis. Figure A2.9a, below, shows the IR
spectrum for compound U, and Figure A2.9b on page 9 shows the
1H NMR spectrum for compound U. In addition, the mass spectrum of
compound U was acquired. A molecular ion peak was observed at
m/z = 166, and the molecular formula for compound U was thereby
determined to be C9H10O3. A peak at m/z = 121 was by far the most
intense peak in the mass spectrum.
Determine the structure of compound U. Be sure to include a concise
discussion of the reasoning you employed to deduce this structure. As
well, construct tables summarizing the IR and 1H NMR data, and assign
the peaks in the IR and NMR spectra to the appropriate structural
elements in U. Your discussion should also include an explanation for the
appearance of the base peak at m/z = 121 in the mass spectrum.
Figure A2.9a: IR spectrum for compound U
Figure A2.9b: 1H NMR spectrum for compound U