Chapter 2 Practice Problems – Answers

Q2.1: Which compound is an expected major organic product of the following sequence of reactions?

Q2.2: Which of the following compounds could not act as the nucleophile in a base-catalyzed aldol reaction?

Q2.3: Which compound is an expected major organic product of the following reaction?

Q2.4: Which compound is an expected major organic product of the following sequence of reactions?

Q2.5: Consider the reaction below. Which of the following best describes the role of the secondary amine in the reaction?

a. catalyst (base catalysis)

b. catalyst (enamine catalysis)

c. catalyst (acid catalysis)

d. solvent

Q2.6: For each reaction draw the expected major organic product(s). The products must be drawn as line-angle structures. Clearly indicate the appropriate stereochemistry using hashed and wedged bonds where necessary. If the product(s) is/are formed as more than one diastereomer, draw all diastereomers formed. If the product(s) is/are formed as a racemate (racemic mixture) draw only one enantiomer and write the word “racemic” beneath/beside it. Do not write “racemic” if it does not apply.

Q2.7: The following molecule undergoes an intramolecular aldol condensation:

Draw all possible products as line-angle structures, accounting for regio- and chemo-selectivity. You may assume the elimination always occurs towards the ketone (i.e. form a conjugated pair of pi bonds). Hint: consider which carbon atom(s) can become nucleophiles.

Bonus question. This question does not have an answer in the key, but is a typical exam question. Draw the likely reaction mechanism for one of the following reactions. Show all reactive intermediates and lone pairs, and use curved arrows to represent the movement of electrons.

No answer key for this question.