Abstract: Dearomatization reactions convert the simple, readily available arenes into more value‑added complex molecules.1 The high resonance energy often renders arenes unreactive as the starting materials. Thereby, the reagents that can overcome this chemical inertness of arenes, are prone to react with the more-reactive unsaturated dearomatized products leading to overreaction and decomposition of the starting material. A conceptually new dearomatization process that involves visible light activation of small heteroatom-containing arenophiles (e.g. N-methyl-1,2,4-triazoline-3,5-dione, MTAD) results in their para-cycloaddition with a variety of nonactivated arenes. The unstable para-cycloadduct was trapped in situ by dihydroxylation,2 or reduction,3 or carboamination4,5 followed by cycloreversion or N–N bond cleavage to provide direct and selective access to highly functionalized cyclohexenes, cyclohexadienes, diaminocyclohexene, hexasubstituted cyclohexane core. Finally, this strategy provides concise synthesis of several biologically active compounds and natural products.
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