RESUMO
A visible-light-induced metal-free cascade cyclization of cyclic N-sulfonyl ketimines with N-arylglycines for the construction of N-sulfonamide-fused imidazolidines was developed. The procedure employed 3 mol% of eosin Y as the photocatalyst at room temperature under visible light irradiation, providing various N-sulfonamide-fused imidazolidines in good yields (32 examples, up to 86% yields).
RESUMO
General photoactivation of electron donor-acceptor (EDA) complexes between arylsulfonium salts and 1,4-diazabicyclo[2.2.2]octane with visible light or natural sunlight was discovered. This practical and efficient mode enables the production of aryl radicals under mild conditions, providing an unrealized opportunity for two-step para-selective C-H functionalization of complex arenes. The novel mode for generating aryl radicals via an EDA complex was well supported by UV-vis absorbance measurements, nuclear magnetic resonance titration experiments, and density functional theory (DFT) calculations. The method was applied to the regio- and stereo-selective arylation of various N-heterocycles under mild conditions, yielding an assembly of challengingly linked heteroaryl-(hetero)aryl products. Remarkably, the meaningful couplings of bioactive molecules with structurally complex drugs or agricultural pharmaceuticals were achieved to display favorable in vitro antitumor activities, which will be of great value in academia or industry.
RESUMO
A sustainable and cost-effective manner for the photocatalytic annulation reaction of N-sulfonyl ketimines with N-arylglycines to synthesize imidazolidine-fused sulfamidates (31 examples) by employing CsPbBr3 as a heterogeneous photocatalyst has been developed. The catalyst CsPbBr3 can be simply recovered from the reaction mixture and reused at least five times without an obvious reduction in its photocatalytic reactivity, exhibiting a high catalyst economic feature.