Write an equation for the reaction of vitamin E with an oxidizing radical (RO•) to give ROH and a less reactive free radical.

For each reaction, show which stereoisomers are obtained

1. NBS/∆/peroxide

2. Br₂/CH₂Cl₂

One danger associated with storing ether solvents is their tendency to form explosive peroxides when exposed to oxygen. Suggest a mechanism by which the hydroperoxide might form. You can assume the presence of X• to start the reaction.

Which ether is most apt to form a peroxide?

Which ether is least apt to form a peroxide?

A student adds NBS to a solution of 1-methylcyclohexene and irradiates the mixture with a sunlamp until all the NBS has reacted. After a careful distillation, the product mixture contains two major products of formula C₇H₁₁Br.

a. Draw the resonance forms of the three possible allylic free radical intermediates.

For each compound, predict the major product of free-radical bromination. Remember that bromination is highly selective, and only the most stable radical will be formed.

(a) cyclohexane

(b) methylcyclopentane

Using the bond-dissociation energies in Table 5.6,

(a) predict whether or not an iodine radical would be selective for forming a single radical propane.

What is the major product of the reaction in Problem 7 when the alkane reacts with Cl₂ instead of with Br₂? Disregard stereoisomers.