Question

catalyses the hydrolysis of the lactum shown here. Propose a mechanism for the metal-ion catalyzed reaction.

Short answer

The answer is,

Step-by-step solution

Catalysis

The catalysis is a process of increasing the reaction rate by using any other external agent which does not take part in reaction as such. Instead they will decrease the initiation energy or by providing suitable intermediate or transition state.

Explanation

The cobalt ion can catalyze the hydrolysis reaction by complexing with three nitrogen atoms in the substrate as well as with water. Complexation increases the acidity of water, thereby providing a better nucleophile (metal-bound hydroxide) for the hydrolysis reaction. Complexation with three nitrogens lock the nucleophile into the correct position for addition to the carbonyl carbon.