Chapter 9 Practice Problems – Answers
Q9.1: Class each of the following as non-aromatic or being/containing aromatic or anti-aromatic systems. If the molecule contains aromatic or anti-aromatic rings/systems circle or highlight the relevant portion(s). Assume any potentially aromatic/anti-aromatic rings/systems are planar.
Drawing resonance forms will help.
Q9.2: What is the hybridization and geometry around the highlighted atoms in these molecules? If an arrow points to a part of the molecule assume it is pointing to the carbon atom there.
Drawing resonance forms will help.
Q9.3: Amy, Bob, and Casey want to practice epoxidation reactions using mCPBA. They are willing to test out any compound as long as at least one epoxidation reaction will occur. Assume the reactions would proceed as discussed in the textbook without complications from other functional groups and that Amy, Bob, and Casey know what they are doing. Indicate (circle, highlight, draw an arrow to, etc.) all of the following molecules they should NOT try because there will be no epoxidation reaction.
Must have one or more alkenes.
“Alkenes” (pi bonds) in aromatic rings will not work.
Alkenes attached to aromatic rings will work.
In reality this can get very complicated;
the assumptions you are given are not always true.
Q9.4: Name each of the following molecules using the IUPAC rules discussed in the text. Be aware that names may be (significantly) longer/shorter than the blank spaces suggest. Use the top line to name the molecule with its formal numbering. Then, if possible, add the equivalent IUPAC name using Greek descriptors (o/m/p) on the second line. If it is not possible to generate a name using the Greek descriptors indicate this in some way.
Strictly following the full IUPAC rules (beyond those covered in the text)
may give slightly different answers for some molecules.
Q9.5: Draw each molecule using the provided IUPAC name.
Note: The numbering of the carbon skeleton for indoles is not straightforward and does not proceed in a simple “clockwise-around-the-ring” fashion. Think critically about where substituents must go to make a valid structure; you should not need to look up how to number indoles to generate the correct answer.
