Synthesis of polycyclic aromatic hydrocarbons by palladium-catalysed [3 + 3] annulation

Abstract

Here we report a new palladium-catalysed [3 + 3] annulation method for the synthesis of polycyclic aromatic hydrocarbons (PAHs) from two smaller aromatic fragments. The successful application to various perylene derivatives is demonstrated based on optimized reaction conditions for the cross-coupling of 1,8-dibromonaphthalene and 4,5-dibromoacenaphthene with various PAH boronic esters. The reported synthetic protocols could be applied for curved and heteroaromatic substrates as well. The structure and packing arrangements of four products were confirmed by single crystal X-ray diffraction.