21. Aldehydes and Ketones: Nucleophilic Addition

What is the major product of each of the following reactions?

b.

When a ketone is dissolved in ¹⁸O-labeled water, the ¹⁸O label is incorporated into the ketone. Suggest a mechanism that explains this observation.

Predict the products formed when cyclohexanone reacts with the following reagents.

(h) sodium acetylide, then mild H₃O⁺

Rank the following compounds from most reactive to least reactive toward nucleophilic addition:

Rank the following compounds from most reactive to least reactive toward nucleophilic addition:

Carbonic anhydrase is an enzyme that catalyzes the conversion of carbon dioxide to bicarbonate ion. It is a metalloenzyme, with Zn²⁺ coordinated at the active site by three histidine side chains. Propose a mechanism for the reaction.

When a cyclic ketone reacts with diazomethane, the next larger cyclic ketone is formed. This is called a ring-expansion reaction. Draw a mechanism for the following ring-expansion reaction.