Question 1

Which of the following best describes the regiochemistry of oxymercuration-demercuration of 2-methyl-2-butene with $$\mathrm{Hg(OAc)_2}$$, $$\mathrm{H_2O}$$, followed by $$\mathrm{$$NaBH_4$$}$$?

Accepted Answer

The OH group adds to the more substituted carbon (Markovnikov addition) without carbocation rearrangement.

Question 2

In the oxymercuration-demercuration of the cyclopentene derivative shown in image 2, what is the stereochemistry of the product?

Accepted Answer

The OH group adds anti to the methyl group.

Question 3

When 2-methyl-2-butene is treated with $$\mathrm{Hg(OAc)_2}$$, $$\mathrm{EtOH}$$, followed by $$\mathrm{$$NaBH_4$$}$$, what is the major product?

Accepted Answer

2-ethoxy-2-methylbutane

Question 4

In the reaction of cyclopentene with $$\mathrm{Hg(OAc)_2}$$, $$\mathrm{$$EtNH_2$$}$$, followed by $$\mathrm{$$NaBH_4$$}$$, what is the major product?

Accepted Answer

N-ethyl-2-cyclopentylamine

Question 5

If the hydration of 2-methyl-2-butene is performed with dilute $$\mathrm{H_2SO_4}$$ instead of oxymercuration-demercuration, what is the expected product?

Accepted Answer

2-methyl-2-butanol, possibly with rearrangement

Question 6

Which of the following statements best explains why oxymercuration-demercuration does not lead to carbocation rearrangement?

Accepted Answer

The reaction proceeds via a three-membered mercurinium ion intermediate, which prevents rearrangement.

Question 7

In the oxymercuration-demercuration of the cyclohexene derivative shown in image 6 with $$\mathrm{t-BuOH} as $$the nucleophile, what is the major product?

Accepted Answer

The tert-butoxy group adds to the more substituted carbon of the double bond.

Question 8

Which of the following best describes the mechanism for the transformation in image 7, where a cyclic ether is converted to a bicyclic amine alcohol?

Accepted Answer

Nucleophilic ring opening by the amine, followed by oxymercuration-demercuration to introduce the alcohol.

Question 9

Which of the following is a key difference between acid-catalyzed hydration and oxymercuration-demercuration of alkenes?

Accepted Answer

Oxymercuration-demercuration avoids carbocation rearrangement, while acid-catalyzed hydration does not.

Question 10

A student performs oxymercuration-demercuration on 1-methylcyclopentene using $$\mathrm{Hg(OAc)_2}$$, $$\mathrm{H_2O}$$, and $$\mathrm{$$NaBH_4$$}. $$Which product is expected?

Accepted Answer

1-methylcyclopentanol with the OH group at the more substituted carbon.

Question 11

Which of the following nucleophiles would result in the formation of an ether during oxymercuration-demercuration of an alkene?

Accepted Answer

$$\mathrm{CH_3OH}$$

Question 12

In the acid-catalyzed hydration of 2-methyl-2-butene, which intermediate is most likely to form?

Accepted Answer

A tertiary carbocation

Question 13

Which of the following best explains why $$\mathrm{$$NaBH_4$$} is $$used in the second step of oxymercuration-demercuration?

Accepted Answer

It reduces the organomercury intermediate to yield the alcohol or ether.

Question 14

A chemist wants to synthesize 2-ethoxy-2-methylbutane from 2-methyl-2-butene. Which reagents should be used?

Accepted Answer

$$\mathrm{Hg(OAc)_2}$$, $$\mathrm{EtOH}$$, $$\mathrm{$$NaBH_4$$}$$

Question 15

Which product is expected when cyclopentene is treated with $$\mathrm{Hg(OAc)_2}$$, $$\mathrm{$$EtNH_2$$}$$, followed by $$\mathrm{$$NaBH_4$$}$$?

Accepted Answer

N-ethylcyclopentylamine

Oxymercuration-Demercuration and Acid-Catalyzed Hydration: Step-by-Step Organic Chemistry Guidance

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