In conclusion, we have discovered an unusual reactivity of imidazolium
carbamate intermediates towards nucleophilic substitution
with halide ions. Our experimental data suggested that the
mechanism of this reaction proceeded via two competitive pathways:
decarboxylative alkyl halide formation involving a nucleophilic
attack at the carboxyl position, or nucleophilic acyl
substitution, which leads to regeneration of the starting alcohol
and dimerization to carbonate byproduct. Further synthetic utilities
of these imidazolium carbamate ions in other useful bondforming
processes are currently being explored in our laboratory.
The results will be reported in due course.