We further investigated the reaction progression of two sets of control experiments of 2-vinylnaphthalene 1a and 4-phenyl-1,3enyne 6a, respectively, in the absence and presence of stoichiometric radical scavenger PhSeSePh under the standard conditions (Figure ). In both cases, the three-component arylative cross-coupling reactions does not proceed and radical-trapping adduct 15 was isolated in high yield, lending support for iminyl radical 2a-A and cyanoalkyl radical 2a-B. In these processes, only cyanoalkyl radical-trapping adduct 15 were observed. Notably, in the presence of phenyl boronic acid 3a, a significant enhancement of formation rate of 15 was observed, implying that phenylboronic acid 3a may facilitate the copper-catalyzed SET-reduction of oxime carbonate 2a to the corresponding cyanoalkyl radical 2a-B through formation of LCu(I)/Ph complex via transmetalation (Figure , i and ii).