Question 1

Which of the following statements best explains why ethers are considered weak bases?

Accepted Answer

Ethers can accept a proton to form a conjugate acid cation, but their lone pairs are less available due to resonance stabilization.

Question 2

Which combination of alkyl halide and alkoxide would give the highest yield of tert-butyl methyl ether via the Williamson ether synthesis?

Accepted Answer

methyl bromide and sodium tert-butoxide

Question 3

What is the major product when 1-hexene is treated with Hg(OAc)$$_2$$, (CH$$_3$$)$$_2$$CHOH, followed by NaBH$$_4$$?

Accepted Answer

2-isopropoxyhexane

Question 4

Which of the following best describes the mechanism for the formation of diethyl ether from ethanol and concentrated H$$_2SO$_4 at 140$^0C$$?

Accepted Answer

S$$_N2 $$substitution

Question 5

Which reagent would you use to oxidize cyclopentene to cis-1,2-cyclopentanediol?

Accepted Answer

KMnO$$_4$$, H$$_2O$$

Question 6

During the acid-catalyzed ring opening of an unsymmetrical epoxide, the nucleophile attacks:

Accepted Answer

The more substituted carbon

Question 7

Which of the following is a correct statement about the stereochemistry of epoxidation of alkenes with peroxycarboxylic acids?

Accepted Answer

The addition is syn and stereospecific.

Question 8

What is the product of the reaction between ethylene oxide and hexylmagnesium bromide followed by aqueous workup?

Accepted Answer

1-octanol

Question 9

Which of the following best explains why epoxides are more reactive toward nucleophilic attack than ethers?

Accepted Answer

Epoxides have significant angle strain in their three-membered ring.

Question 10

Which of the following statements about the oxidative cleavage of glycols with periodic acid (H$$_5IO$_6) is $$correct?

Accepted Answer

The C–C bond between the two OH groups is cleaved to give aldehydes and/or ketones.

Question 11

Which of the following is true regarding the reaction of organocuprates with epoxides?

Accepted Answer

The reaction proceeds via an S$$_N2 $$mechanism at the less substituted carbon.

Question 12

Which of the following best describes the product of the reaction between 1-bromo-2-methyl-2-propanol and NaOH?

Accepted Answer

2,2-dimethyloxirane

Question 13

Which of the following is a key difference between the cleavage of ethers with primary alkyl groups and tertiary alkyl groups?

Accepted Answer

Primary alkyl ethers undergo S$$_N2 $$cleavage, while tertiary alkyl ethers undergo S$$_N1 $$cleavage.

Question 14

Which of the following is the most reactive toward nucleophilic substitution: a trialkyloxonium ion, a trialkylsulfonium ion, or a neutral ether?

Accepted Answer

Trialkyloxonium ion

Question 15

Which of the following best explains why intramolecular reactions are often faster than their intermolecular counterparts?

Accepted Answer

The nucleophile and electrophile are already 'tied together,' reducing the need for random diffusion.

Question 16

Which of the following is the correct product for the acid-catalyzed ring opening of 2,2-dimethyloxirane with methanol?

Accepted Answer

2-methoxy-2-methyl-1-propanol (with nucleophile attacking the more substituted carbon)

Question 17

Which of the following statements about the stereochemistry of glycol formation from alkenes using OsO$$_4 is $$correct?

Accepted Answer

The addition of OH groups is syn and stereospecific.

Question 18

Which of the following is a correct statement about the reaction of Grignard reagents with epoxides?

Accepted Answer

The reaction extends the carbon chain by two carbons.

Question 19

Which of the following best describes the regioselectivity of nucleophilic attack on an unsymmetrical epoxide under basic conditions?

Accepted Answer

The nucleophile attacks the less substituted carbon.

Chapter 12: The Chemistry of Ethers, Epoxides, Glycols, and Sulfides – Study Notes

Study Guide - Practice Questions