Transition-Metal-Free Decarboxylative Cyclization of N-Arylacrylamides with 2,2-Difluoro-2-(phenylthio)acetic Acid: Synthesis of Thiodifluorooxindole Derivatives.

An efficient transition-metal-free decarboxylative cyclization of N-arylacrylamides with 2,2-difluoro-2-(phenylthio)acetic acid for the construction of thiodifluoroindoleone derivatives is described. This strategy features stable and readily available substrates, mild reaction conditions, and transition-metal-free catalysts. Notably, this protocol has successfully applied to synthesis of gem-difluoroalkenes, which exist in numerous biologically active compounds.

Visible-Light-Promoted Cross-Coupling Reactions of 4-Alkyl-1,4-dihydropyridines with Thiosulfonate or Selenium Sulfonate: A Unified Approach to Sulfides, Selenides, and Sulfoxides.

In this paper, a visible-light-promoted cross-coupling of 4-alkyl-1,4-dihydropyridines with thio-/selenium sulfonates under transition-metal-free conditions is described. This strategy features easily available substrates, mild reaction conditions, high yields, and high chemoselectivity. A novel synthetic route for the construction of a sulfide or selenide Csp3-S or Csp3-Se bond under transition-metal-free conditions without an additive oxidant or base is developed. This method is well extended to the synthesis of a class of thiolated or selenylated glycosides that has not been explored before. Sulfoxides were also successfully chemoselectively observed via a facile variation of the atmosphere under photocatalyzed conditions.