The cation pool method serves as a powerful tool for electroorganic synthesis.¹ In the cation pool method organic cations are electrochemically generated and accumulated in solution at low temperatures. Reactions with subsequently added nucleophiles give the desired products. However, the cation pool method cannot be applied to highly unstable cations that decompose during the course of the electrolysis. To expand the scope of the cation pool method, we have developed the stabilized cation pool method, in which electrochemically generated organic cations are stabilized by suitable stabilizing agents and are accumulated in solution. The reactions of the stabilized organic cations with subsequently added nucleophiles give the desired products. We have already reported that the method is successfully applied to benzylic C−H/ aromatic C−H cross-coupling.²

In this paper we show that vinyl C−H/ aromatic C−H cross-coupling can be achieved. I-O-S⁺R₂ generated by oxidation of I₂ in the presence of O=SR₂³ adds to ArCH=CH₂ to generate and accumulate the corresponding α-(iodomethyl)beznylaminosulfonium ions as stabilized benzyl cations. In the next step, the (α-iodomethyl)beznylaminosulfonium ions are reacted with subsequently added electron-rich aromatic compounds (Ar’H) as nucleophiles. The elimination of HI with a base gives ArAr’C=CH₂ to achieve metal- and oxidant-free formal vinylic C-H/aromatic C-H cross coupling.

1. Yoshida, J.; Ashikari, Y.; Matsumoto, K.; Nokami, T. J. Synth. Org. Chem., Jpn. 2013, 1136.
2. Hayashi, R.; Shimizu, A.; Yoshida, J. J. Am. Chem. Soc. 2016, 138, 8400.
3. Ashikari, Y.; Shimizu, A.; Nokami, T.; Yoshida, J. J. Am. Chem. Soc. 2013, 135, 16070.