In search of the spin-delocalization effect from the correlation analysis of relative rates of the trichloromethyl-bromo-addition reactions to fourteen p-Y-substituted phenylacetylenes

Article abstract of DOI:10.1016/0040-4020(96)00021-X

A rigorous procedure was applied to the measurement of the relative rates, i.e. k(r)(Y) = k(Y)/k(H) of trichloromethyl-bromo-addition reactions to fourteen p-Y-substituted phenylacetylenes (I-Y, with Y = F, Cl, Br, Me, t-Bu, OMe, SMe, SiMe₃, CF₃, CN, NO₂, SOMe, COMe, and CO₂Me). The reaction was run in cyclohexane under nitrogen antmosphere at 65 ± 0.5°C. All products were derived from the intermediate YC₆H₄C = CHCCl₃ adduct radicals. Correlation analysis of these rate data seems to suggest that both a polar and a spin-delocalization effect are operating at the transition state.