Show how you would accomplish the following syntheses.

c. hexan-1-ol → 2-hydroxyheptanoic acid

Propose mechanisms for the three imine-forming reactions just shown.

Depending on the reaction conditions, two different imines of formula C₈H₉N might be formed by the reaction of benzaldehyde with methylamine. Explain, and give the structures of the two imines.

Show how hex-1-yne might be converted to

d. 1,1,2,2-tetrabromohexane.

Give the structures of the carbonyl compound and the amine used to form the following imines.

(a)

(b)

(c)

Give the structures of the carbonyl compound and the amine used to form the following imines.

(d)

(e)

(f)

Propose a mechanism for the hydrolysis of benzaldehyde methyl imine just shown.

2,4-Dinitrophenylhydrazine is frequently used for making derivatives of ketones and aldehydes because the products (2,4-dinitrophenylhydrazones, called 2,4-DNP derivatives) are even more likely than the phenylhydrazones to be solids with sharp melting points. Propose a mechanism for the reaction of acetone with 2,4-dinitrophenylhydrazine in a mildly acidic solution.

Predict the products of the following reactions.

(a)

(b)

Predict the products of the following reactions.

(c)

(d)

Show what amines and carbonyl compounds combine to give the following derivatives.

(a)

(b)

(c)

Show what amines and carbonyl compounds combine to give the following derivatives.

(d)

Show what amines and carbonyl compounds combine to give the following derivatives.

(e)

Show what amines and carbonyl compounds combine to give the following derivatives.

(f)

Propose a mechanism for the acid-catalyzed reaction of benzaldehyde with methanol to give benzaldehyde dimethyl acetal.

Propose a mechanism for the acid-catalyzed hydrolysis of cyclohexanone dimethyl acetal.

Show what alcohols and carbonyl compounds give the following derivatives.

(a)

(b)

(c)

In the mechanism for acetal hydrolysis shown, the ring oxygen atom was protonated first, the ring was cleaved, and then the methoxy group was lost. The mechanism could also be written to show the methoxy oxygen protonating and cleaving first, followed by ring cleavage. Draw this alternative mechanism.

Propose a mechanism for the acid-catalyzed reaction of cyclohexanone with ethylene glycol to give cyclohexanone ethylene acetal.

Propose a mechanism for the acid-catalyzed hydrolysis of cyclohexanone ethylene acetal.

Propose a mechanism for the acid-catalyzed hydrolysis of the acetal given in Problem 18-26(f).

Show how you would accomplish the following syntheses. You may use whatever additional reagents you need.

(a)

Show how you would accomplish the following syntheses. You may use whatever additional reagents you need.

(b)

Show how you would accomplish the following syntheses. You may use whatever additional reagents you need.

(c)

Show how you would accomplish the following syntheses. You may use whatever additional reagents you need.

(d)

Show how you would accomplish the following syntheses. You may use whatever additional reagents you need.

(e)

Show how you would accomplish the following syntheses. You may use whatever additional reagents you need.

(f)

Trimethylphosphine is a stronger nucleophile than triphenylphosphine, but it is rarely used to make ylides. Why is trimethylphosphine unsuitable for making most phosphorus ylides?

Write the sequence of steps required for the conversion of benzene into benzenediazonium chloride.

Like other strong nucleophiles, triphenylphosphine attacks and opens epoxides. The initial product (a betaine) quickly cyclizes to an oxaphosphetane that collapses to an alkene and triphenylphosphine oxide.

(a) Show each step in the reaction of trans-2,3-epoxybutane with triphenylphosphine to give but-2-ene. What is the stereochemistry of the double bond in the product?