Aromatic ring assembly from acyclic precursors (benzannulation) has been the subject of considerable study in recent years. 1 Advances in this field based on Fischer carbene complexes (the Dötz reaction), 2 cobalt-mediated alkyne cyclotrimerization, 3 cyclobutenone and cyclobutenedione rearrangements, 4 vinyl ketene cycloaddition, 5 as well as other cyclization protocols6 permit construction of a wide range of fused arene ring systems, ...
