An efficient Pd/Cu-catalyzed
oxidative self-carbonylation of arylhydrazine with CO and molecular
oxygen as an oxidant to afford symmetrical biaryl ketones via C-N bond
activation has been developed. In this approach, arylhydrazine
hydrochlorides are used as a green arylating agent which releases
nitrogen and water as a byproduct. This developed protocol significantly
restricts the formation of aryl iodide and homo-coupled azobenzene
products even under favorable conditions. A library of symmetrical
biaryl ketones with wide functionalities was synthesized in good yields
under mild conditions.
|