Synthesis and Spectroscopy
1. Provided below is the IR and 1
H NMR for a compound having the molecular formula of
C7H14O2. Using this information, determine the degrees of unsaturation for this structure and
solve and draw the structure responsible for these spectral data. To validate your answer, you
need to assign the type of bond (ie. stretch) responsible for each peak highlighted by a box in
the IR. You must also assign each 1H NMR peak (a)-(e) to the correct set of protons in your
proposed structure. The integration for each peak has been provided for you. You must label
the multiplicity observed for each peak. Is your structure consistent with all of this data? If
not, chances are you do not have the correct structure, or the peaks have been assigned
incorrectly. In your peer review, offer feedback concerning the accuracy of the submitted
structures and spectral assignments. If you believe the answers are incorrect, then you need to
provided explanation. In the end, you should all be getting the same correct structure. Please
draw the final structure in the box provided underneath the NMR.
1H NMR – for clarity, expansions have been provided for peaks that are not a singlets.
Proposed Structure: Remember to assign it to the NMR per instructions.
2. Below is a synthetic scheme that is missing the structure of the desired product. This product
is the same structure that you solved for in prompt 1 using the molecular formula, IR and NMR
data. Draw the structure of the desired product (hint, it has one degree of unsaturation but is
not an alkene or a ring). Starting from 1-bromo-2-methylbutane, design a multi-step synthesis
for this desired product. Your synthetic plan may not use any SN1 or E1 reactions. You
may only use SN2 reactions, reactions that involve the use of PBr3, SOCl2, or TsCl, E2
reactions, and any necessary alkene addition reaction from chapter 8 (including the
reaction discussed in chapter 10.5).
Separate each individual reaction in your proposal with a reaction arrow. For each step, write
in the reagents necessary to carry out each step either above or below the reaction arrow. Also
draw the expected product for each step after each reaction arrow. For reactions types where
more than one regioisomer product is possible, you must use reagents that are regiospecific.
For example, in E2 reactions, the choice of bulky base or non-bulky base can dictate which
alkene is formed preferentially. Also, several (but not all) of the alkene addition reactions
learned in chapter 8 and 10.5 are regiospecific and are either Markovnikov or AntiMarkovnikov addition reactions. Please indicate which steps this was important to consider.
Your reagent choices should address these concerns appropriately. Discuss with your peers
alternative approaches that would be better should you feel that a step is incorrect.
Furthermore, discuss with your peers any other synthetic routes that would have led to the
Synthetic Transformation Desired
IR FREQUENCY TABLE (in wavenumber)
NMR CHEMICAL SHIFT TABLE (in ppm)