Alkanes are directly iodinated by perfluoroalkyl iodides by a free-radical chain process initiated by t-BuOOH in acetic acid solution. The initially formed iodoalkanes are reduced back to alkanes by excess t-BuOOH; the rate constant for hydrogen abstraction from t-BuOOH by a primary alkyl radical has been roughly evaluated to be similar to 10(4) M-1 s(-1). Two new procedures for the reductive alkylation of alkenes by t-BuOOH and Pb(OAc)(4) are reported. The importance of the polar effects and the rate constants of the key elementary steps involved in these processes is discussed.