Mechanisms of the rupture of the carbon-tin bond by halogens I. Electrophilic substitution at a saturated carbon atom

Article abstract of DOI:10.1016/S0022-328X(00)91016-7

The reaction between halogens and tetraalkyltins is strongly influeced by the dielectric constant, the polarisability and the nucleophilicity of the solvent. These three aspects of solvent action are relatd to the ability of tin to make use of its empty 5d orbitals: the Sn polarisation, enhanced by the pentaco-ordination of the metal, governs the reactivity of the alkyl groups attached to it, appropriate attention being given to the incursion of steric effects. In polar media, the solvent itself acts as the nucleophilic catalyst and the reaction is best described by the following scheme {A figure is presented}. In less active solvents, the halogen molecule plays the role of nucleophile in a predetermining step the most likely mechanism may be written as follows: {A figure is presented}.