Question 1

Which reagent would you use to convert a cyclohexanone to a cyclohexene via a Wittig reaction?

Accepted Answer

$$\mathrm{Ph_3P=CH_2$}$$

Question 2

What is the major product when benzaldehyde reacts with methyl iodide and triphenylphosphine followed by NaOH?

Accepted Answer

Styrene ($$\mathrm{C_6H_5CH=CH_2$})$$

Question 3

Which of the following best describes the mechanism of the Swern oxidation?

Accepted Answer

Oxidation of alcohols to carbonyls using DMSO, oxalyl chloride, and a base

Question 4

In the mechanism for the E2 elimination of tert-butyl bromide in methanol, which step is rate-determining?

Accepted Answer

Simultaneous removal of a proton and loss of bromide ion

Question 5

Which reagent is used to selectively reduce an ester to an aldehyde?

Accepted Answer

$$\mathrm{1. DIBAL-H, -78^\circ C}$$ 
$$2. H_2O$$

Question 6

What is the product of the reaction between benzaldehyde and ethylene glycol in the presence of an acid catalyst?

Accepted Answer

A cyclic acetal

Question 7

Which of the following is the correct order of reactivity for the reduction of carbonyl compounds with NaBH$$_4$$?

Accepted Answer

Aldehyde \u003e Ketone \u003e Ester

Question 8

In the Wolff-Kishner reduction, what is the role of hydrazine ($$\mathrm{NH_2NH_2}$$)?

Accepted Answer

It forms a hydrazone intermediate with the carbonyl compound

Question 9

Which of the following transformations is achieved using PCC (pyridinium chlorochromate)?

Accepted Answer

Oxidation of a primary alcohol to an aldehyde

Question 10

Which of the following best describes the product of the reaction: 
$$\mathrm{$$PhCOCH_3$$} \xrightarrow{1. MeI, NaOMe} \xrightarrow{2. H_3O^+}$$

Accepted Answer

A methylated ketone ($$\mathrm{PhCOCH_2CH_3})$$

Question 11

Which of the following is a correct statement about the mechanism of imine formation from a ketone and methylamine under mildly acidic conditions?

Accepted Answer

The reaction proceeds via a carbinolamine intermediate

Question 12

Which of the following reagents would you use to convert a benzaldehyde to a benzoic acid?

Accepted Answer

$$\mathrm{$$KMnO_4$$, H_2O, \Delta}$$

Question 13

Which of the following best describes the outcome of the reaction: 
$$\mathrm{$$PhCOCH_3$$} \xrightarrow{1. LDA, 2. PhCH_2Br}$$

Accepted Answer

Alkylation at the alpha position to give $$\mathrm{PhCOCH_2CH_2Ph}$$

Question 14

Which of the following is the correct sequence of reagents to convert a methyl ketone to a 3-methylcyclohexenone?

Accepted Answer

$$1. \mathrm{MeI, LDA} \ 2. \mathrm{NaOEt, EtOH} \ 3. \mathrm{H_3O^+}$$

Question 15

Which of the following statements about the Swern oxidation is correct?

Accepted Answer

It converts primary alcohols to aldehydes without over-oxidation to carboxylic acids

Question 16

In the mechanism for the SN2 reaction of 1-bromopentane with sodium hydroxide, which of the following is true?

Accepted Answer

The reaction proceeds with inversion of configuration at the carbon center

Question 17

Which of the following best describes the product of the reaction: 
$$\mathrm{$$PhCOCH_3$$} \xrightarrow{1. DIBAL-H, -78^\circ C} \xrightarrow{2. H_2O}$$

Accepted Answer

An aldehyde ($$\mathrm{PhCH_2CHO})$$

Question 18

Which of the following is a correct statement about the Wolff-Kishner reduction?

Accepted Answer

It reduces carbonyl groups to methylene groups under basic conditions

Question 19

Which of the following is the correct product for the reaction: 
$$\mathrm{$$PhCOCH_3$$} \xrightarrow{1. MeI, NaOMe} \xrightarrow{2. H_3O^+}$$

Accepted Answer

A methylated ketone ($$\mathrm{PhCOCH_2CH_3})$$

Exam 1 Practice: Organic Chemistry Reaction Mechanisms and Synthesis

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