Alpha Substitution Reactions Quiz

What is the main difference between base-catalyzed and base-promoted reactions?

• Base-catalyzed reactions regenerate the base, while base-promoted reactions consume it.

• Base-promoted reactions regenerate the base, while base-catalyzed reactions consume it.

• Both reactions consume the base.

• Both reactions regenerate the base.

In a base-catalyzed mechanism, what is the role of the enolate?

• It acts as a solvent.

• It acts as an electrophile.

• It acts as a catalyst.

• It acts as a nucleophile.

Why is the major resonance contributor important in base-catalyzed mechanisms?

• It is only important for predicting products.

• It is not used in the mechanism.

• It is used for accurate arrow pushing.

• It is less stable than the minor contributor.

What happens to the electrophile in a base-catalyzed reaction?

• It is attached to the beta carbon.

• It is removed from the reaction.

• It is attached to the alpha carbon.

• It is converted into a nucleophile.

What is the first step in an acid-catalyzed mechanism?

• Addition of an electrophile.

• Deprotonation of the alpha hydrogen.

• Tautomerization of the ketone.

• Formation of an enolate.

In an acid-catalyzed mechanism, what is the nucleophile?

• Base

• Enolate

• Electrophile

• Enol

What is the final step in an acid-catalyzed mechanism?

• Formation of a pi bond.

• Addition of an electrophile.

• Deprotonation of the oxygen.

• Tautomerization.

Which of the following is true about the acid-catalyzed mechanism?

• It involves the formation of an enol.

• It involves the formation of an enolate.

• It does not involve tautomerization.

• It is more fun to do the arrow pushing than the base-catalyzed mechanism.

What is typically used as the base in the final deprotonation step of an acid-catalyzed mechanism?

• Conjugate base of the acid used

• Water

• Any strong acid

• H3O+

What is the key takeaway regarding nucleophiles in base and acid-catalyzed mechanisms?

• Enolates are nucleophiles in both mechanisms.

• Enolates are nucleophiles in base-catalyzed, and enols in acid-catalyzed mechanisms.

• Enols are nucleophiles in base-catalyzed, and enolates in acid-catalyzed mechanisms.

• Enols are nucleophiles in both mechanisms.