10. Addition Reactions

Predict the product(s) of each of the following reactions, making sure to indicate the relative stereochemical outcome. Indicate any racemic mixtures by drawing both enantiomers.

(b)

Predict the product(s) of each of the following reactions, making sure to indicate the relative stereochemical outcome. Indicate any racemic mixtures by drawing both enantiomers.

(f)

In which of the two steps in the alkene halogenation mechanism does a redox reaction occur?

Bromination of a highly electron-rich alkene such as 2-methoxybut-2-ene has been shown to produce approximately equal mixtures of the trans- and cis-dibromide. Suggest an explanation for this observation.

In Chapter 19, we discuss the reaction of enols with bromine. This reaction produces α -bromoketones in good yields. Suggest a mechanism for this reaction and justify its deviation from the dibromide product you might have expected.

Identify A through O:

Predict the product of the following addition reactions to dienes.

(c)

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (i) Br₂ (ii) Cl₂.

(e)

Provide an arrow-pushing mechanism that rationalizes the stereospecific formation of each dihalide in Assessment 9.6.

Predict the product(s) that would result when the alkenes are allowed to react under the following conditions: (i) Br₂ (ii) Cl₂

(f)

Predict the product of the following haloalkane syntheses.

(a)

Predict the product(s) of each of the following reactions, making sure to indicate the relative stereochemical outcome. Indicate any racemic mixtures by drawing both enantiomers.

(c)

In spite of being mechanistically similar to some of the reactions we saw in Chapter 8, rearrangement never occurred here in Chapter 9. Why doesn't rearrangement occur in the following bromination reaction despite the proximity of a more substituted carbon?

In contrast to the addition of Br₂ the addition of HBr [Section 8.3] is not stereospecific. Why?

Show how each of the following compounds can be synthesized from an alkene:

b.