Dehydrogenative Synthesis of Quinolines, 2-Aminoquinolines, and Quinazolines Using Singlet Diradical Ni(II)-Catalysts

Simple, straightforward and atom economic methods for the synthesis of quinolines, 2-aminoquinolines and quinazolines via bio-mimetic dehydrogenative condensation/coupling reactions, catalyzed by well defined inexpensive and easy to prepare singlet di-radical Ni(II)-catalysts featuring two antiferromagnetically coupled singlet di-radical diamine type ligands are described. Various polysubstituted quinolines, 2-aminoquinolines and quinazolines were synthesized in moderate to good yields from different low-cost and readily accessible starting materials. Several control experiments were carried out to get insight into the reaction mechanism which shows that the nickel and the coordinated diamine ligands participate in a synergistic way during the dehydrogenation of alcohols.