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.

(c)

Draw the products of the following reactions. If the products can exist as stereoisomers, show which stereoisomers are formed.

c.

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

(b)

Propose mechanisms and predict the major products of the following reactions. Include stereochemistry where appropriate.

(c) (E)-dec-3-ene + Br₂ in CCl₄

(d) (Z)-dec-3-ene + Br₂ in CCl₄

Problem-Solving Hint: Models may be helpful whenever stereochemistry is involved. Write complete structures, including all bonds and charges, when writing mechanisms.

Give mechanisms to account for the stereochemistry of the products observed from the addition of bromine to cis- and trans-but-2-ene (Figure 8-5). Why are two products formed from the cis isomer but only one from the trans? (Making models will be ­helpful.)

What is the major product of each of the following reactions, assuming that one equivalent of each reagent is used in each reaction?

b.

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (i) Br₂

(d)

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (ii) Cl₂

(d)

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (i) Br₂

(h)