Hydrogen-Atom-Transfer-Mediated Acceptorless Dehydrogenative Cross-Coupling Enabled by Multiple Catalytic Functions of Zwitterionic Triazolium Amidate

An unconventional cooperative catalysis for hydrogen-atom-transfer-mediated acceptorless dehydrogenative cross-coupling is described. The combined use of zwitterionic 1,2,3-triazolium amidate and an Ir-based photosensitizer as catalysts enables C–H/C–H cross-couplings between heteroatom-containing C–H donors and enamides or 1,1-diarylethenes under visible-light irradiation without the need for any oxidants, hydrogen evolution catalysts, or electrodes. A key to establishing this catalysis is the susceptibility of the conjugate acid of the triazolium amidate, amide triazolium, toward single-electron reduction to complete the catalytic cycle.