Deuterium kinetic isotope effects in β-elimination from phenethyl bromide promoted by para-substituted sodium phenoxides in dimethyl-formamide

Deuterium kinetic isotope effects have been measured for elimination from phenethyl bromide promoted by para-substituted sodium phenoxides in dimethylformamide. Despite the large basicity range considered variations in the magnitude (in the range 7·6–9·0) of the isotope effects were practically within experimental error. Some evidence for proton tunnelling was obtained and this has made difficult a straightforward interpretation of the k2H/k2D values in terms of transition state geometry.