March 2023

A nickel-catalyzed C–Se cross-coupling between aryl iodides and selenols is described. The newly developed catalytic methodology offers facile access to various unsymmetrical selenium-containing motifs. The reaction features excellent functional group tolerance, wide substrate scope, good efficiency, and operates under mild reaction conditions. Notably, this protocol could be readily scaled up to gram scale without the loss of yield.

A transition-metal- and organic-solvent-free oxidative coupling of thiols catalyzed by BrCCl3 and NaOH in an aqueous medium with oxygen as a green oxidant was established The facile and green method has a broad substrate scope in converting thiols into the corresponding disulfides with medium to excellent yields (up to 91%). This method could potentially be used to construct bioactive molecules containing disulfide bonds and to label bioactive molecules with disulfide bonds.

An efficient iodine-catalyzed cascade coupling protocol was developed for the synthesis of tetracyclic and pentacyclic pyrrolo[1,2-a]quinoxaline and indolo[1,2-a]quinoxaline derivatives via the iodine-mediated oxidative Pictet–Spengler reaction of 2-(1H-pyrrol-1-yl)aniline or 2-(1H-indol-1-yl)aniline with ninhydrin followed by spirocyclic ring opening with alcohol/water. The target compounds were obtained in good-to-excellent yields with a broad substrate scope.