Question 1

Which reagent would you use to convert a cyclohexanol to cyclohexanone without rearrangement?

Accepted Answer

PCC

Question 2

How many distinct $^1$H NMR signals would you expect for the following molecule?

$\displaystyle \mathrm{CH_3CH_2CH_2CH_3}$

Accepted Answer

2

Question 3

Which of the following best describes the major product of the reaction of 2-methyl-2-butanol with HBr?

Accepted Answer

2-bromo-2-methylbutane

Question 4

A student attempts to synthesize 2-butanol from ethene using only ethene as the carbon source. Which of the following sequences would be most effective?

Accepted Answer

Ethene $\xrightarrow{HBr}$ bromoethane $\xrightarrow{NaOH}$ ethanol $\xrightarrow{Grignard, acetaldehyde}$ 2-butanol

Question 5

Which of the following statements about the $^1$H NMR chemical shift of a hydrogen attached to a carbon adjacent to a carbonyl group is correct?

Accepted Answer

It appears downfield, typically between $2.0$ and $2.5$ ppm.

Question 6

In the reaction of cyclohexene with Br$_2$ in water, what is the major organic product?

Accepted Answer

1-bromo-2-hydroxycyclohexane

Question 7

Which of the following mechanisms best explains the formation of a racemic mixture when 2-butanol reacts with HBr?

Accepted Answer

SN1 mechanism

Question 8

What is the expected product when cyclohexanone is treated with NaBH$_4$?

Accepted Answer

Cyclohexanol

Question 9

Which of the following reagents would convert a primary alcohol to a primary alkyl chloride?

Accepted Answer

SOCl$_2$

Question 10

How many $^1$H NMR signals would you expect for 1,2-dimethylcyclopentane?

Accepted Answer

5

Question 11

Which of the following best describes the role of PCC in organic synthesis?

Accepted Answer

It oxidizes primary alcohols to aldehydes.

Question 12

In the $^1$H NMR spectrum, which hydrogen would appear furthest downfield?

Accepted Answer

Hydrogen on a benzene ring

Question 13

Which of the following transformations would require the use of a bulky base to favor elimination over substitution?

Accepted Answer

Conversion of 2-bromopropane to propene

Question 14

Which of the following is the correct IUPAC name for the structure shown below?

$\displaystyle \mathrm{CH_3CH(CH_3)CH_2CH_2CH_3}$

Accepted Answer

3-methylpentane

Question 15

Which of the following best explains why the reaction of cyclohexanol with HBr produces a racemic mixture?

Accepted Answer

The reaction proceeds via a carbocation intermediate, allowing attack from either side.

Question 16

What is the major product when 1-methylcyclohexene reacts with Br$_2$ in water?

Accepted Answer

1-bromo-2-hydroxy-1-methylcyclohexane

Question 17

Which of the following is a correct step in the mechanism for the reaction of 2-methyl-2-butanol with HBr?

Accepted Answer

Protonation of the alcohol to form a good leaving group

Question 18

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

Accepted Answer

NaBH$_4$

Question 19

In a synthesis, which reagent would you use to convert an alkene to a vicinal diol?

Accepted Answer

OsO$_4$ followed by H$_2$O$_2$

Organic Chemistry Exam Study Guide: Structure, Mechanisms, and Spectroscopy

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