21. Aldehydes and Ketones: Nucleophilic Addition

Show how the following compounds can be synthesized from cyclohexanol.

a. b. c.

Propose a mechanism for each of the following reactions:

a.

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

(a) PhMgBr, then H₃O⁺

LOOKING AHEAD CHAPTERS 8, 17 In Chapters 8 and 17 we learn two reaction for the synthesis of the alcohol shown. (a) Show a mechanism for each of the reactions. (b) If you were designing a synthetic route, which would be considered more sustainable? Consider all factors. [Assume the starting organic molecules are equally green.]

Rank the following compounds from largest K_eq to smallest K_eq for hydrate formation:

Can the rate of hydrate formation be increased by hydroxide ion as well as by acid? Explain.

Which of the following are a. hemiacetals? b. acetals? c. hydrates?

4.

Rank the following carbonyl compounds in order of increasing equilibrium constant for hydration:

CH₃COCH₂Cl ClCH₂CHO CH₂O CH₃COCH₃ CH₃CHO

What are the products of the following reactions?

e.

f.

Draw structures of the following derivatives.

(f) the methyl hemiacetal of formaldehyde

For each compound,

1. name the functional group.

2. show what compound(s) result from complete hydrolysis.

(b)

Explain why acetals do not react with nucleophiles.

Propose a mechanism for each of the following reactions:

b.

Which ketone forms the most hydrate in an aqueous solution?

Which of the following are a. hemiacetals? b. acetals? c. hydrates?

2.