7. Substitution Reactions

Using the given starting material, any necessary inorganic reagents and catalysts, and any carbon-containing compounds with no more than three carbons, indicate how each of the following compounds can be prepared:

a.

For each reaction, give the expected substitution product, and predict whether the ­mechanism will be predominantly first order (S_N1) or second order (S_N2).

a. 2-chloro-2-methylbutane + CH₃COOH

b. isobutylbromide + sodium methoxide

Show how you might use S_N2 reactions to convert 1-chlorobutane into the following compounds.

a. butan-1-ol

Show how you might use S_N2 reactions to convert 1-chlorobutane into the following compounds.

b. 1-fluorobutane

A solution of pure (S)-2-iodobutane ([α] = +15.90°) in acetone is allowed to react with radioactive iodide, ¹³¹I^–, until 1.0% of the iodobutane contains radioactive iodine. The specific rotation of this recovered iodobutane is found to be +15.58°.

b. What does this result suggest about the mechanism of the reaction of 2-iodobutane with iodide ion?

Show how you would convert (in one or two steps) 1-phenylpropane to the three products shown below. In each case, explain what unwanted reactions might produce undesirable impurities in the product.

Using cyclohexane as one of your starting materials, show how you would synthesize the following compounds.

(c)

Alkylbenzyldimethyl ammonium chloride is a leave-on skin antiseptic used to treat such things as cuts and cold sores. It is also the antiseptic in many hand sanitizers. It is actually a mixture of compounds that differ in the number of carbons (any even number between 8 and 18) in the alkyl group. Show three different sets of reagents (each set composed of an alkyl chloride and an amine) that can be used to synthesize the alkylbenzyldimethyl ammonium chloride shown here.

Which reaction in each of the following pairs takes place more rapidly? (EtOH is ethyl alcohol; Et₂O is diethyl ether.)

d.

e.

Under which of the following reaction conditions will (R)-1-chloro-1-phenylethane form the most (R)-1-phenyl-1-ethanol: in water or in 1.0 M HO⁻?

Draw the substitution products for each of the following reactions; if the products can exist as stereoisomers, show what stereoisomers are obtained:

e. 1-bromo-2-butene + CH₃O⁻

f. 1-bromo-2-butene + CH₃OH

Suggest a reagent to carry out each of the following conversions to an alcohol.

(a)

When (R)-(1-bromoethyl)benzene is treated with sodium cyanide, a single enantiomer is produced. However, upon treatment of the same molecule with water, a mixture of two enantiomers is obtained.

(a) Explain these results.

(b) Why is only partial racemization sometimes observed?

Order the following molecules on the basis of their nucleophilic strength using the pKₐ values of their conjugate acids.

Suggest a reagent to carry out each of the following conversions to an alcohol.

(c)