Predict the product(s) of the following nucleophilic aromatic substitution reactions occurring by the benzyne mechanism.

(b)

Predict the products of the following reactions.

(a)

Conversion of t-butylbenzene to a phenol results in two products when the reaction occurs through the benzyne mechanism. Devise a sequence involving a diazonium ion in which only one phenol product is produced.

Predict the products of the following reactions.

(a)

Predict the products of the following reactions.

(b)

Suggest two coupling partners that could be used to synthesize the compounds shown making the indicated C―C bonds.

(a)

(i) Classify the following molecules as aromatic, nonaromatic, or antiaromatic.

(ii) For aromatic molecules, solve for n in Hückel’s rule. For all other molecules, explain which rule of aromaticity is being broken.

(a)

(i) Classify the following molecules as aromatic, nonaromatic, or antiaromatic.

(ii) For aromatic molecules, solve for n in Hückel’s rule. For all other molecules, explain which rule of aromaticity is being broken.

(b)

(i) Classify the following molecules as aromatic, nonaromatic, or antiaromatic.

(ii) For aromatic molecules, solve for n in Hückel’s rule. For all other molecules, explain which rule of aromaticity is being broken.

(c)

(i) Classify the following molecules as aromatic, nonaromatic, or antiaromatic.

(ii) For aromatic molecules, solve for n in Hückel’s rule. For all other molecules, explain which rule of aromaticity is being broken.

(d)

(i) Classify the following molecules as aromatic, nonaromatic, or antiaromatic.

(ii) For aromatic molecules, solve for n in Hückel’s rule. For all other molecules, explain which rule of aromaticity is being broken.

(e)

(i) Classify the following molecules as aromatic, nonaromatic, or antiaromatic.

(ii) For aromatic molecules, solve for n in Hückel’s rule. For all other molecules, explain which rule of aromaticity is being broken.

(f)

(i) Classify the following molecules as aromatic, nonaromatic, or antiaromatic.

(ii) For aromatic molecules, solve for n in Hückel’s rule. For all other molecules, explain which rule of aromaticity is being broken.

(g)

(i) Classify the following molecules as aromatic, nonaromatic, or antiaromatic.

(ii) For aromatic molecules, solve for n in Hückel’s rule. For all other molecules, explain which rule of aromaticity is being broken.

(h)

(i) Classify the following molecules as aromatic, nonaromatic, or antiaromatic.

(ii) For aromatic molecules, solve for n in Hückel’s rule. For all other molecules, explain which rule of aromaticity is being broken.

(i)

Use a Frost circle diagram to construct the molecular orbital diagram for the molecules shown. Would you expect them to be aromatic or antiaromatic?

(a)

Use a Frost circle diagram to construct the molecular orbital diagram for the molecules shown. Would you expect them to be aromatic or antiaromatic?

(b) 

Use a Frost circle diagram to construct the molecular orbital diagram for the molecules shown. Would you expect them to be aromatic or antiaromatic?

(c)

Using a Frost circle, a student drew the molecular orbital picture shown for the cyclopentadienyl anion, determining it to be antiaromatic. Do you agree with this conclusion? Why or why not?

Despite having only sp²-hybridized carbons and having 10 electrons (4n + 2) , the annulene shown is not aromatic. Why?

In Section 17.7.4, we studied the acid-catalyzed hydrolysis of acetals. The acetal shown here resists hydrolysis by the mechanism in Figure 17.63. Why? [Draw the intermediates as if the reaction would occur, then analyze the intermediates for any problems.]

Molecule A is significantly more water soluble than molecule B. Justify this observation.

Predict the major product(s) that would result when molecules (a)–(i) are allowed to react under the following conditions. (iv) chlorocyclopentane, AlCl₃, (v) 1-chloro-1-methylcyclohexane , AlCl₃, (vi) PhCOCl, AlCl₃. If no reaction will occur, indicate by writing NR.

(a)

Suggest a synthesis of each of the molecules shown beginning with benzene.

(c)

Bromination of phenol or aniline does not require the use of a Lewis acid catalyst and often results in trihalogenation. Why?

Protonation of aniline slows electrophilic aromatic substitution and directs electrophiles to the meta position. Why?

Indigo is a dye that was originally isolated from coal tar. In 1905, Johann Friedrich Wilhelm Adolf von Baeyer won a Nobel Prize for a method that allowed indigo to be isolated from plants [a green chemist ahead of his time.] If you nitrated indigo using the reaction learned in this chapter, at which carbon would you expect the nitro group to attach?

Would you expect chlorination to occur ortho, para, or meta to the pyridinium ion in the following molecule? Explain your answer.

Fluoxetine, an antidepressant, is better known as Prozac®. Suggest reagents that could be used to make the indicated C–O bond of fluoxetine. [Note that CF₃, an electron-withdrawing group, is para to where the new bond will be formed.]

Acetohexamide is used to treat type 2 diabetes that cannot be well controlled by diet alone. Fill in the blanks of the synthetic scheme used to synthesize acetohexamide. [Hints have been provided below each step.]