Copper-Catalyzed Sulfonylation Reaction of NH-Sulfoximines with Aryldiazonium Tetrafluoroborates and Sulfur Dioxide: Formation of <i>N</i>‑Sulfonyl Sulfoximines

An efficient and practical SO2 insertion protocol of NH-sulfoximines with aryldiazonium tetrafluoroborates and DABSO toward N-sulfonyl sulfoximines has been developed under mildly basic conditions. This transformation features easy operation, readily available substrates, and mild conditions. A tentative mechanism is proposed, which indicates that the aryldiazonium tetrafluoroborates would be radical donors under standard reaction conditions. The aryl radical produced in situ from diazonium salts would be trapped by SO2 to generate an arylsulfonyl radical and then undergo further transformation to generate the final N-sulfonyl sulfoximines

Copper-Catalyzed Divergent C–H Functionalization Reaction of Quinoxalin-2(1<i>H</i>)‑ones and Alkynes Controlled by N1-Substituents for the Synthesis of (<i>Z</i>)‑Enaminones and Furo[2,3‑<i>b</i>]quinoxalines

With control by N1-substituents, the switchable divergent C–H functionalization reaction of quinoxalin-2­(1H)-ones is achieved for the synthesis of (Z)-enaminones and furo­[2,3-b]­quinoxalines using the combination of a copper catalyst and an oxidant. This new protocol features mild reaction conditions, readily available materials, and a broad substrate scope. Gram-scale and mechanistic studies were also investigated. Furthermore, the desired products exhibited excellent antitumor activity against A549, HepG-2, MCF-7, and HeLa cells, which were tested by MTT assay

Selective Electrochemical Halogenation of Functionalized Quinolone

This work describes an effective C3–H halogenation of quinoline-4(1H)-ones under electrochemical conditions, in which potassium halides serve as both halogenating agents and electrolytes. The protocol provides expedient access to different halogenated quinoline-4(1H)-ones with unique regioselectivity, broad substrate scope, and gram-scale synthesis employing convenient, environmentally friendly electrolysis, in an undivided cell. Mechanism studies have shown that halogen radicals can promote the activation of N–H bonds in quinolones