10. Addition Reactions

(••) Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (vii) 1. mCPBA 2. (viii) 1. O₃ 2. CH₃SCH₃.

(e) <IMAGE>

Draw the product(s) you'd expect when each of these alkenes is treated first with O₃, then with Ch₃SCH₃

(d) <IMAGE>

(••) Predict the product of ozonolysis of the triglyceride shown.

<IMAGE>

Assessments 11.62–11.65 should be answered in order.

(•••) Predict the product of the following benzylic bromination reactions.

(a) <IMAGE>

Predict the product of the following aldehyde/ketone syntheses.

(a) <IMAGE>

Predict the product of the following aldehyde/ketone syntheses.

(a) <IMAGE>

(•••) Ozonolysis of an unknown alkene A gives the products shown. Predict the product that results from hydrogenation of alkene A. [There are multiple answers, but only show the one with the 6-membered ring.]

<IMAGE>

(••) Suggest reagents to carry out the following transformation. [One of the answers should be from Chapter 9.]

<IMAGE>

Draw the product(s) you'd expect when each of these alkenes is treated first with O₃, then with Ch₃SCH₃

(b) <IMAGE>

Suggest a synthesis of the following aldehydes or ketones using the ozonolysis reaction of an alkene.

(b) <IMAGE>

(••) Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (vii) 1. mCPBA 2. (viii) 1. O₃ 2. CH₃SCH₃

(l) <IMAGE>

(••) Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (vii) 1. mCPBA 2. (viii) 1. O₃ 2. CH₃SCH₃

(f) <IMAGE>

Draw the product(s) you'd expect when each of these alkenes is treated first with O₃, then with Ch₃SCH₃

(c) <IMAGE>

b. What alkenes would give only an aldehyde with four carbons as a product of oxidative cleavage

What are the products of the following reactions? Indicate whether each reaction is an oxidation or a reduction.

a. <IMAGE>

What are the products of the following reactions? Indicate whether each reaction is an oxidation or a reduction.

c. <IMAGE>

For each compound, show the products obtained from ozonolysis, followed by treatment with dimethyl sulfide.

e. <IMAGE>

What alkene gives the product shown after reaction first with ozone and then with dimethyl sulfide?

a. <IMAGE>

What alkene gives the product shown after reaction first with ozone and then with dimethyl sulfide?

c. <IMAGE>

b. The following products were obtained from the oxidative cleavage of a diene. What is the structure of the diene?

[SOLVED]

What products are formed when the following compounds react with ozone and then with dimethyl sulfide?

c. <IMAGE>

d. <IMAGE>

The following product was obtained from the ozonolysis of an alkene followed by treatment with dimethyl sulfide. What is the structure of the alkene?

a. <IMAGE>

The following product was obtained from the ozonolysis of an alkene followed by treatment with dimethyl sulfide. What is the structure of the alkene?

b. <IMAGE>

One of the constituents of turpentine is α-pinene, formula C10H6. The following scheme (called a “road map”) gives some reactions of α-pinene. Determine the structure of α-pinene and of the reaction products of A through E

<IMAGE>

Problem 8-54 describes a new method to perform ozonolysis reactions that used pyridine (py) to generate the final

aldehydes and ketones in a non-aqueous reaction medium. In a subsequent publication (J. Org. Chem., 2013, 78, 42),

Professor Dussault (U. of Nebraska at Lincoln) described a “tandem” process in which two reactions are performed

sequentially without having to isolate the intermediate aldehyde or ketone. Show the final product from each sequence.

(Hint: The isolated products were from the larger part of the structure. Ignore stereochemistry.)

(a) <IMAGE>

(b) <IMAGE>

Problem 8-54 describes a new method to perform ozonolysis reactions that used pyridine (py) to generate the final

aldehydes and ketones in a non-aqueous reaction medium. In a subsequent publication (J. Org. Chem., 2013, 78, 42),

Professor Dussault (U. of Nebraska at Lincoln) described a “tandem” process in which two reactions are performed

sequentially without having to isolate the intermediate aldehyde or ketone. Show the final product from each sequence.

(Hint: The isolated products were from the larger part of the structure. Ignore stereochemistry.)

(c) <IMAGE>

(d) <IMAGE>

Deduce the structure of each compound from the information given. All unknowns in this problem have molecular formula C8H12.

(c) Upon catalytic hydrogenation, unknown Y gives cyclooctane. Ozonolysis of Y, followed by reduction with dimethyl sulfide, gives a three-carbon dialdehyde and a five-carbon dialdehyde. Draw the structure of Y.

(d) Upon catalytic hydrogenation, unknown Z gives cis-bicyclo[4.2.0]octane. Ozonolysis of Z, followed by reduction with dimethyl sulfide, gives a cyclobutane with a three-carbon aldehyde (-CH2-CH2-CHO) group on C1 and a one-carbon aldehyde (-CHO) group on C2. Draw the structure of Z.

Predict the major products of the following reactions, and give the structures of any intermediates. Include stereochemistry where appropriate.

d. <IMAGE>

Professor Patrick Dussault (University of Nebraska at Lincoln) has developed an alternative to the standard two-step ozonolysis procedure requiring reduction of the ozonide in a second step. He uses 2 to 3 equivalents of pyridine, a mildly basic organic solvent, in a one-step process (Organic Letters, 2012, 14, 2242). Show the products you expect from the following examples.

a. <IMAGE>

b. <IMAGE>

Give structures of the alkenes that would give the following products upon ozonolysis–reduction.

c. <IMAGE> and <IMAGE>

Using 1,2-dimethylcyclohexene as your starting material, show how you would synthesize the following compounds. (Once you have shown how to synthesize a compound, you may use it as the starting material in any later parts of this problem.) If a chiral product is shown, assume that it is part of a racemic mixture. <IMAGE>

i. <IMAGE>

Show how you would synthesize each compound using

methylenecyclohexane as your starting material.

<IMAGE>

d. <IMAGE>

Ozonolysis can be applied selectively to different types of carbon–carbon double bonds. The compound shown below contains two vinyl ether double bonds, which are electron-rich because of the electron-donating alkoxy groups. Ozone reacts more quickly with electron-rich double bonds and more slowly with hindered double bonds. At −78 °C, this compound quickly adds two equivalents of ozone. Immediate reduction of the ozonide gives a good yield of a single product. Show the expected ozonolyis product, and label the functional groups produced, some of which are not typical from ozonolysis of simple alkenes.

<IMAGE>

Professor Patrick Dussault (University of Nebraska at Lincoln) has developed an alternative to the standard two-step ozonolysis procedure requiring reduction of the ozonide in a second step. He uses 2 to 3 equivalents of pyridine, a mildly basic organic solvent, in a one-step process (Organic Letters, 2012, 14, 2242). Show the products you expect from the following examples.

c. <IMAGE>

d. <IMAGE>

Predict the major products of the following reactions.

c. <IMAGE> + O3, then (CH3)2S

d.1-ethylcycloheptene + ozone, then (CH3)2S

Problem-Solving Hint: Three reagents oxidize the pi bond of an alkene but leave the sigma bond intact: (a) cold, dilute KMnO4; (b) OsO4-H2O2; and (c) RCO3H epoxidation.

Two reagents break the double bond entirely, giving carbonyl groups: (a) warm, concentrated KMnO4 and (b) O3 followed by (CH3)2S.

What products are formed when the following compounds react with ozone and then with dimethyl sulfide?

e. <IMAGE>

f. <IMAGE>

Ozonolysis of an alkene, followed by treatment with dimethyl sulfide, forms the following product(s). Identify the alkene in each case.

a. <IMAGE>

What is the major product of the reaction of 2-methyl-2-butene with each of the following reagents?

d. O₃, −78 °C, followed by (CH₃)₂S

What aspect of the structure of the alkene does ozonolysis not tell you?