Sequentially Pd/Cu‐Catalyzed Alkynylation‐Oxidation Synthesis of 1,2‐Diketones and Consecutive One‐Pot Generation of Quinoxalines

Abstract

We report a simple and efficient one‐pot synthesis of 1,2‐diketones by concatenation of two Pd/Cu‐catalyzed processes: Pd0/CuI‐catalyzed Sonogashira coupling of terminal alkynes with aryl (pseudo)halides furnishes internal alkynes, which are directly transformed by PdII/CuII‐catalyzed Wacker‐type oxidation with DMSO and oxygen as dual oxidants to furnish 1,2‐diketones. With this efficient, catalyst economical process, various aryl iodides and triflates are efficiently transformed in high yields into symmetrically and unsymmetrically substituted 1,2‐diketones with various functional groups. This process can be readily extended to a consecutive one‐pot synthesis of quinoxalines in a diversity‐oriented fashion.