The Cross‐Dehydrogenative Coupling Reaction of β‐Ketoesters with Quinoxalin‐2(1 H )‐ones

Metal-Free Addition of Alkyl Bromides to Access 3,3-Disubstituted Quinoxalinones Enabled by Visible-Light Photoredox Catalysis

A metal-free addition of unactivated alkyl bromides to quinoxalin-2(1H)-ones is described. This method enables the construction of valuable 3,3-disubstituted dihydroquinoxalin-2(1H)-ones bearing quaternary carbon centers under mild, visible-light photoredox catalysis. High functional group tolerance is observed in both the quinoxalinone and alkyl bromide partners. The ability to scale up this method was demonstrated under photo-flow conditions to enable gram-scale synthesis.

Lewis-Acid-Catalyzed Selective Friedel-Crafts Reaction or Annulation between Anilines and Glyoxylates

A Lewis-acid-catalyzed selective reaction between anilines and glyoxylates was developed for synthesis of diarylmethanes or oxoimidazolidines. Under the catalysis of AgOTf, a series of anilines-based diarylmethanes, including primary, secondary, and tertiary anilines, were obtained in moderate to good yields. Moreover, stereoselective oxoimidazolidines were performed with the catalysis of Cu(OAc)₂·H₂O.

Decatungstate-Photocatalyzed Direct Coupling of Inert Alkanes and Quinoxalin-2(1H)-ones with H2 Evolution

A tetrabutylammonium decatungstate (TBADT)-photocatalyzed direct coupling of inert alkanes and quinoxalin-2(1H)-ones with H2 evolution was developed at room temperature. The present transformation achieved the direct C(sp3)-H/C(sp2)-H coupling under noble metal-free,...