Pd/C-mediated Synthesis of 2,3-diyne-1,4-naphthoquinone Derivatives via dual C-C Bond Forming Reaction in a Single Step

A dual carbon-carbon bond formation between 2,3-dibromo-1,4-naphthoquinone and terminal alkynes in EtOH was efficiently facilitated by a combination of catalysts e.g. 10%Pd/C-Cu-PPh3 affording a handy and single-step synthesis of 2,3-diyne-1,4-naphthoquinones. The methodology afforded desired products possessing potential medicinal value in acceptable yields. A probable mechanism accounting the dual C-C bond forming reaction has been proposed.