Dearomatizationr eactions represent av ersatile approach for the preparation of three-dimensionally (3D) privileged cyclic moieties from simple planar aromatic compounds.H owever, exogeneous oxidants are required for most of the radical ando xidative dearomatizations.T herefore,s ustainable proceduresa re in high demand, especially those in the absence of external oxidizing reagents.F ortunately, electrolytic dearomatization protocols can fulfill the abover equirements due to the manipulation of traceless electrons insteado fc hemicals during the processes. Nevertheless,s ustainable electrochemical dearomative transformationsh ave been farl ess frequently investigated than the well-developed chemical dearomatizationr eactions.H erein, we summarize representativeb reakthroughs in the electrochemical dearomative transformation of indoles,f urans and activated arenes (phenols anda nisoles) for the synthesis of complicated skeletons.H opefully,t his interesting "simplicity-to-complexity" synthetic logic will inspire more innovations from the electroorganic community.Scheme 28. Electrochemical dearomatizationo fthe phenylpropenoid system for generating quinone methide dimers.

Transition‐metal‐catalyzed C−H activation has attracted much attention from the organic synthetic community because it obviates the need to prefunctionalize substrates. However, superstoichiometric chemical oxidants, such as copper‐ or silver‐based metal oxidants, benzoquinones, organic peroxides, K2S2O8, hypervalent iodine, and O2, are required for most of the reactions. Thus, the development of environmentally benign and user‐friendly C−H bond activation protocols, in the absence of chemical oxidants, are urgently desired. The inherent advantages and unique characteristics of organic electrosynthesis make fill this gap. Herein, recent progress in this area (until the end of September 2018) is summarized for different transition metals to highlight the potential sustainability of electro‐organic chemistry.

Herein, an environmentally friendly electrochemical approach is reported that takes advantage of the captodative effect and delocalization effect to generate nitrogen‐centered radicals (NCRs). By changing the reaction parameters of the electrode material and feedstock solubility, dearomatization enabled a selective dehydrogenative C−N versus N−N bond formation reaction. Hence, pyrido[1,2‐a]benzimidazole and tetraarylhydrazine frameworks were prepared through a sustainable transition‐metal‐ and exogenous oxidant‐free strategy with broad generality. Bioactivity assays demonstrated that pyrido[1,2‐a]benzimidazoles displayed antimicrobial activity and cytotoxicity against human cancer cells. Compound 21 exhibited good photochemical properties with a large Stokes shift (approximately 130 nm) and was successfully applied to subcellular imaging. A preliminary mechanism investigation and density functional theory (DFT) calculations revealed the possible reaction pathway.