α-Silicon- and α-alkynyl-substituted vinyl cations

Article abstract of DOI:10.1021/jo00314a600

The solvolytic reactivity of a number of silicon- and alkynyl-substituted vinyl triflates was investigated in aqueous ethanol.Activation parameters and solvent m values were determined for all subtrates.Relative rate data show that the Me₃Si group is accelerating and hence stabilizing relative to hydrogen but destabilizing relative to a t-Bu group.The α-ethynyl substituent causes a rate decrease compared to a methyl group despite its ?-donating resonance ability.These results are discussed.