Palladium-Catalyzed\nDouble Decarboxylative [3 + 2]\nAnnulation of Naphthalic Anhydrides with Internal Alkynes

A palladium-catalyzed [3 + 2] annulation of naphthalic\nanhydrides\nwith internal alkynes has been developed. The present protocol offers\nan efficient and convenient route to access a series of 1,2-disubstituted\nacenaphthylenes with excellent functional group compatibility. The\nreaction is proposed to proceed through a double decarboxylation sequence.\nThe reported synthetic protocols can be extended to napthalene- and\nperylenedicarboximide-containing substrates. The molecular structures,\nphotophysical properties, and frontier molecular orbitals of the obtained\nadducts were investigated by X-ray crystallography, UV–vis\nand fluorescence spectroscopy, and DFT calculations.