Fragmentation of β-Silyl Radicals. A Computational Study

beta-Fragmentation of beta-silyl radical species can be considered as a potent source of silyl radical species that should find useful applications in tin-free radical processes. A computational study on the evaluation of the substituents effects both at silicon and on the alpha- and beta-carbons of beta-silyl radical species on the rate of the beta-fragmentation step is presented. Density functional theory was used to determine the activation and reaction energies of beta-fragmentation of the radical precursors. Single-point computations at the B3LYP/6-311++G(d,p)//B3LYP/6-31G(d) and ROMP2/6-31G(d)//B3LYP/6-31G(d) level were further performed to obtain more precise energy predictions. The obtained results allow establishing structure properties relationships linking the activation barrier of the beta-fragmentation process to the nature of the substituents, which should help in predicting the structure of the most efficient beta-silyl radical precursors.