Lecture 15

Question 1

Base catalysis

Answer 1

Increases the rate of reaction by deprotonating a reactant

Question 2

Nucleophilic catalysis

Answer 2

Increases the rate of reaction by forming a new covalent bond to one of the reactants
-complete change in the reaction mechanism

Question 3

Metal Ion Catalysis

Answer 3

• Metal ions are strong lewis acids that form donor-acceptor complexes with molecules that have lone pairs
• Coordination of a metal ion to a carbonyl group has the same effect as adding a proton
• The donor-acceptor complex is more reactive to nucleophiles than the free carbonyl compound

Question 4

Metal Ion versatility

Answer 4

In some cases metal ions play the same catalytic role as a proton

• metal ions are stronger lewis acids than protons, most have charge greater than +1
• coordination to a carbonyl group enhances the reactivity of an electrophile
• coordination to water enhances the reactivity of the nucleophile