Isocyanurate Anion Radicals via Electron-initiated Cycloaddition of lsocyanates

Room temperature sodium metal reductions of alkyl isocyanates lead to the rapid electron-initiated formation of alkyl isocyanurate anion radicals, which exhibit EPR coupling to only two equivalent nitrogens. Reduction of C-13-enriched ethyl isocyanate reveals that the odd electron localizes in the pi system of one carbonyl in the isocyanurate ring. EPR line-width alternation effects indicate that at least two stable conformers are in rapid equilibrium undergoing fast exchange.