Electrochemical 1,2‐Diarylation of Alkenes Enabled by Direct Dual C–H Functionalizations of Electron‐Rich Aromatic Hydrocarbons

Abstract A cobalt‐promoted electrochemical 1,2‐diarylation of alkenes with electron‐rich aromatic hydrocarbons via direct dual C−H functionalizations is described, which employs a radical relay strategy to produce polyaryl‐functionalized alkanes. Simply by using graphite rod cathode instead of platinum plate cathode, chemoselectivity of this radical relay strategy is shifted to the dehydrogenative [2+2+2] cycloaddition via 1,2‐diarylation, annulation, and dehydrogenation cascades leading to complex 11,12‐dihydroindolo[2,3‐ a ]carbazoles. Mechanistical studies indicate that a key step for the radical relay processes is transformations of the aromatic hydrocarbons to the aryl sp 2 ‐hybridized carbon‐centered radicals via deprotonation of the corresponding aryl radical cation intermediates with bases.