Question 1

Which of the following statements best explains why tertiary carbocations are more stable than primary carbocations?

Accepted Answer

Tertiary carbocations are stabilized by hyperconjugation from three adjacent alkyl groups.

Question 2

Given the molecule $$(R)-1,1,1-$$trifluoro-$$3,3-$$dimethyl-$$2-$$butanol, which of the following best describes its stereochemistry?

Accepted Answer

It has one stereocenter and is optically active.

Question 3

Which reagent would you use to convert a secondary alcohol to a ketone?

Accepted Answer

H$$_2$$CrO$$_4$$

Question 4

What is the relationship between the following two molecules: $$(1R,2S,3S)-2-$$bromo-3-methylcyclohexanol and $$(1S,2R,3R)-2-$$bromo-3-methylcyclohexanol?

Accepted Answer

They are enantiomers.

Question 5

Which of the following alcohols is the strongest acid?

Accepted Answer

$$CF_3CH_2OH$$

Question 6

In an $$S_N2$$ reaction, which of the following substrates will react fastest?

Accepted Answer

A primary alkyl bromide

Question 7

Which of the following best describes the energy diagram for an $$E1$$ reaction mechanism?

Accepted Answer

Two transition states separated by a carbocation intermediate.

Question 8

What is the product of the reaction between cyclohexanone and NaBH$$_4$$?

Accepted Answer

Cyclohexanol

Question 9

How many stereocenters are present in the molecule epothilone C?

Accepted Answer

8

Question 10

Which of the following carbocations cannot be stabilized by hyperconjugation?

Accepted Answer

A methyl carbocation ($$CH_3$$^+$$)

Question 11

What is the major product when 2-bromopentane reacts with NaSCH$$_3$$?

Accepted Answer

2-methylthiopentane

Question 12

Which of the following best describes the relationship between 1-chloro-2-methylcyclopropane and 2-chloro-1-methylcyclopropane?

Accepted Answer

They are structural isomers.

Question 13

Which of the following reagents would you use to reduce a ketone to a secondary alcohol?

Accepted Answer

NaBH$$_4$$

Question 14

Which of the following is the correct order of acidity for the alcohols: $$CH_3CH_2OH$$, $$CF_3CH_2OH$$, $$CH_3CH_2CH_2OH$$?

Accepted Answer

$$CF_3CH_2OH \u003e CH_3CH_2OH \u003e CH_3CH_2CH_2OH$$

Question 15

Which of the following is the best description of the product formed when a Grignard reagent reacts with a ketone followed by aqueous workup?

Accepted Answer

A tertiary alcohol

Question 16

What is the expected product when 2-bromopentane is treated with NaN$$_3$$?

Accepted Answer

2-azidopentane

Question 17

Which of the following best explains why $$CF_3CH_2OH is a $$stronger acid than $$CH_3CH_2OH$$?

Accepted Answer

The trifluoromethyl group withdraws electron density, stabilizing the conjugate base.

Question 18

Which of the following is the correct order of reactivity for $$S_N2$$ reactions: methyl bromide, ethyl bromide, isopropyl bromide?

Accepted Answer

Methyl bromide \u003e ethyl bromide \u003e isopropyl bromide

Question 19

Which of the following is a correct synthetic route to convert ethane to 2-methyl-2-propanol?

Accepted Answer

Brominate ethane, react with Mg to form Grignard, then react with acetone followed by aqueous workup.

Organic Chemistry II: Stereochemistry, Reaction Mechanisms, and Synthesis – Exam Study Guide

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