Preparation and Evaluation of Sterically Hindered Acridine Photocatalysts

Abstract A practical nickel‐catalyzed protocol for the synthesis of sterically hindered 9‐arylacridines via Negishi type cross‐coupling was developed. The method enables a convenient approach to a set of active acridine photocatalysts starting from commercially available 9‐chloroacridine, inexpensive catalyst [NiCl 2 (Ph 3 P) 2 ], and organozinc reagent with no need for additional ligands and precious metals. The synthetic protocol could be readily performed on a gram scale. The photocatalytic efficiency of obtained acridines was tested in decarboxylative thiolation and amination reactions. Structures of 19 acridines were studied by X‐ray analysis, which allowed to propose a steric descriptor relevant to the catalytic activity. magnified image