10. Addition Reactions

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

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.

Give the products expected when the following compounds are ozonized and reduced.

(c)

(d)

Predict the products of the following reaction.

Draw the product(s) you'd expect when each of these alkenes is treated first with O₃, then with CH₃SCH₃

(b)

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.

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (vii) 1. mCPBA 2. H₂SO₄, H₂O (viii) 1. O₃ 2. CH₃SCH₃

(l)

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

(k)

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

(h)

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

e.

What hydrocarbon forms the following products after reaction first with ozone and then with dimethyl sulfide?

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)

(d)

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

a.

Predict the major products of the following reactions.

(a) (E)-3-methyloct-3-ene + ozone, then (CH₃)₂S

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

(a)