7. Substitution Reactions

Predict the product of the following substitution reactions, paying close attention to the stereochemical outcome of the reactions.

(d)

Which of the following substitution reactions would you expect to occur more quickly? Explain your answer.

Predict the product of the substitution reactions, paying attention to the stereochemical outcome.

(b)

Crown ethers are able to solvate cations based on their size. Specifically, 15-crown-5 forms stable complexes with sodium. How would the addition of a crown ether change the rate of an S_N2 reaction?

To solve this problem, you need to read the description of the Hammett $\sigma$, $\rho$ treatment given in [Chapter 15, Problem 92]. When the rate constants for the hydrolysis of several morpholine enamines of para-substituted propiophenones are determined at pH 4.7, the $\rho$ value is positive; however, when the rates of hydrolysis are determined at pH 10.4, the $\rho$ value is negative.

b. What is the rate-determining step of the hydrolysis reaction when it is carried out in an acidic solution?

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Predict the product for the following substitution reactions. Indicate whether each reaction likely proceeds by an S_N1 or S_N2 mechanism.

(b)

Predict the product for the following substitution reactions. Indicate whether each reaction likely proceeds by an S_N1 or S_N2 mechanism.

(c)

Predict the product(s) of the following reactions.

(h)

The benzylic bromide shown undergoes neither S_N1 nor S_N2 substitution reactions. Explain.

Predict the product for the following substitution reactions. Indicate whether each reaction likely proceeds by an S_N1 or S_N2 mechanism.

(a)

Would you expect the following substitution reaction to proceed with inversion or racemization? Why?

Predict the product of the following substitution reactions, making sure to note whether a rearrangement should occur.

(a)

Give a mechanism for the following substitution and elimination reactions.

(c)

Would the following nucleophiles be more likely to participate in an S_N1 or S_N2 reaction?

(c)

For each solvent, indicate the most likely substitution reaction to take place.

(a)