Relay Catalysis by a Multifunctional Cu Catalyst in a Tandem Dehydro-/Dehalogenation Sequence along with N‑Arylation

A Cu-catalyzed tandem dehydrogenation/dehalogenation sequential reaction along with N-arylation has been developed for the synthesis of pyridazinone derivatives in an aerobic and aqueous environment. To achieve the transformation of three chemical bonds in a one-pot reaction, a multifunctional copper catalyst was used which afforded excellent activity, high selectivity, and recyclability. The catalytic system consists of a water-soluble Cusalen complex and Na2CO3 in neat water and an air atmosphere.