Provide a mechanism for the chlorination of cyclohexane. Be sure to include initiation, propagation, and three possible termination steps.

Predict the major monohalogenation product(s) of the following reactions. Indicate whether you think the reaction will be selective and justify your position.

(c)

Predict the product(s) of the following halogenation reactions. Only one equivalent of the halogen is used in each case. If the reaction proceeds selectively, indicate this by only drawing the major product. If the reaction is not selective, draw all possible products.

(e)

Predict the product(s) of the following halogenation reactions. Only one equivalent of the halogen is used in each case. If the reaction proceeds selectively, indicate this by only drawing the major product. If the reaction is not selective, draw all possible products.

(f)

We have studied the following reactions in previous chapters. For each, (i) indicate which reaction sheets they should appear on, (ii) show the best structure to use to represent them, and (iii) write the notes you could put in the margin so that the mechanism is implied.

(b) Radical halogenation of an alkane

For the following reaction, answer questions (a)–(d).

(a) Give an arrow-pushing mechanism, including the initiation step and two propagation steps.

Predict the major products of the following alkane halogenation reactions. [The number of products shown ignores the formation of racemic mixtures.]

(c)

Other molecules can be used as initiators in radical reactions. One such molecule is 2, 2'-azobisisobutyronitrile (AIBN). Show an arrow-pushing mechanism that rationalizes the formation of the following radical species. What are the driving forces of this reaction?

Cyclizations can be carried out under radical conditions involving Bu₃SnH and a catalytic amount of AIBN. Suggest a mechanism for this reaction. [Pay close attention to the bonds formed and broken in developing your mechanism. It may be helpful to number the carbons.]