Abstract: Iodide ion promotes the free radical addition of t-BuHgI to acrylonitrile to form t- BuCH? CH (CN) HgI. A facile reaction of the adduct 1-cyanoalkyl radical with t-BuHgIz-is indicated. Further promotion is observed in the presence of NI&I or PTSA/KI in a reaction now leading directly to t-BuCH2CH2CN. Protonation of the intermediate adduct radical followed by electron transfer from t-BuHgI2-is postulated. With fumaronitrile reaction of the ...