A set of radical clock experiments using (bromomethyl)cyclopropane (2F) or 6iodohex-1-ene (2G) was carried out (Figure ). We observed the ring-opened product (6aF) from the cyclopropylmethyl radical and the cyclized products (4aG, 6aG) from the 5-hexenyl radical. Furthermore, the ratio of uncyclized (6aG')/cyclized (6aG) products exhibited a linear correlation with the nickel catalyst concentration. These observations indicated the noncage radical nature of this reaction.