Question 1

Which of the following best describes the product of the reaction between cyclohexanone and Ph$$_3P=CH$_2 ($$Wittig reagent)?

Accepted Answer

Methylene cyclohexane

Question 2

When 2-butanone reacts with Ph$$_3P=CH$_2$$, what is the major organic product?

Accepted Answer

2-Methyl-2-butene

Question 3

What is the expected product when benzaldehyde reacts with Ph$$_3P=$$CHCH$$_3$$?

Accepted Answer

Trans-β-methylstyrene

Question 4

A reaction between a cyclic ketone and a Wittig reagent produces which type of functional group in the product?

Accepted Answer

Alkene

Question 5

Which of the following best explains why the Wittig reaction is useful in organic synthesis?

Accepted Answer

It forms carbon-carbon double bonds with control over alkene geometry.

Question 6

Given the reaction of an α,β-unsaturated ketone with a Wittig reagent, what is the most likely major product?

Accepted Answer

A conjugated diene

Question 7

In the reaction of a ketone with a stabilized ylide (e.g., Ph$$_3P=$$CHCO$$_2Et$$), what is the major product?

Accepted Answer

An alkene with E-selectivity

Question 8

Which of the following statements about the mechanism of the Wittig reaction is correct?

Accepted Answer

The reaction proceeds via a four-membered oxaphosphetane intermediate.

Question 9

A chemist wants to synthesize 1-phenyl-1-butene from benzaldehyde. Which Wittig reagent should be used?

Accepted Answer

Ph$$_3P=$$CHCH$$_2CH$_3$$

Question 10

Which of the following is a common side product of the Wittig reaction?

Accepted Answer

Triphenylphosphine oxide

Question 11

If a chemist reacts acetophenone with Ph$$_3P=CH$_2$$, what is the major product?

Accepted Answer

Styrene

Question 12

Which of the following best describes the stereochemistry of alkenes formed from unstabilized Wittig reagents?

Accepted Answer

Predominantly Z-alkenes

Question 13

A student attempts a Wittig reaction with a ketone and a stabilized ylide but observes a low yield. Which of the following is a likely reason?

Accepted Answer

Stabilized ylides are less reactive, leading to lower yields with ketones.

Question 14

Which of the following best explains why the Wittig reaction is not suitable for the synthesis of tetrasubstituted alkenes?

Accepted Answer

Steric hindrance prevents the formation of the oxaphosphetane intermediate.

Question 15

Which of the following is the correct order of reactivity of carbonyl compounds in the Wittig reaction (most to least reactive)?

Accepted Answer

Aldehyde \u003e Ketone \u003e Ester

Question 16

A chemist wants to synthesize (E)-stilbene from benzaldehyde. Which ylide should be used?

Accepted Answer

A stabilized ylide such as Ph$$_3P=$$CHCO$$_2Et$$

Organic Chemistry: Nucleophilic Substitution and Elimination Reactions – Major Product Prediction

Study Guide - Practice Questions