Benzylidene bromide reacts with unsaturated compounds CH2=CHR (R = Bu, SiMe(3)) in the presence of benzoyl peroxide to give PhCHBrCH(2)CHRBr adducts.

Radical telomerization of vinyl chloride with benzyl bromide and the competitive reaction of benzyl bromide with vinyl chloride and trimethylvinylsilane have been studied. The relative rate constant for the addition of C6H5C · H2 to vinyl chloride,krel (with respect to trimethylvinylsilane), is close to unity, whereas the activation energy of the addition of C6H5C.H2 to vinyl chloride is considerably lower (by 7 kcal mol−1) than in the reaction involving trimethylvinylsilane. The possible fragmentation of the radical-adduct C6H5CH2CH2C.HCl was suggested as one of the possible reasons of underestimation ofkrel. The activation energy was estimated by the MPDO/3 method.

The general kinetics of the addition of benzyl bromide to trimethylvinylsilane in the presence of the Fe(CO)5—DMF system has been studied. The reaction orders with respect to each reagent found in the study correspond to a radical chain mechanism of the process. The metal-complex system takes part only in the initiation stage and only at a strictly defined ratio of the components.

Radical addition of benzyl bromide to unsaturated compounds containing substituents of a different polar nature, CH2=CHX (X=C4H9, SiMe3, CF3, CO2Me, CN, H), was conducted in the presence of the Fe(CO)5 + DMF (HMPA) system. Adducts were obtained and their structure was demonstrated by13C NMR and mass spectrometry.

The relative rate constants of the addition of the C6H5CH2 radical to unsaturated compounds CH2=CHX (X = C4H9, SiMe3, CF3, CO2Me, CN) were determined under the conditions of initiation by the Fe(CO)5 + DMF system or by benzoyl peroxide. Depending on the values of the relative addition rate constants, the monomers can be arranged into the following series (X): CF3≈C4H9<SiMe3<CO2Me<CN. The relatively nucleophilic character of the benzyl radical has been shown. It was found that under the initiation conditions by the Fe(CO)5 + DMF system, the addition stage proceeds by a free radical mechanism.