Several highly substituted naphthalenes 3 have been synthesized in a one-pot reaction by treatment of arenes 1 with alkynes 2 in the presence of palladium acetate and silver acetate. In this Pd-catalyzed protocol, an arene provides a benzo source for the construction of a naphthalene core through twofold aryl C-H bond activation. Reaction of triphenylphosphine with diphenylethyne (2 a) under the catalysis of Pd(IV) complexes produced 1,2,3,4-tetraphenylnaphthalene (3 ba) in 62 % yield. Here, triphenylphosphine undergoes one aryl C-P bond cleavage and one aryl C-H bond activation to serve as a benzo moiety. Crystal structures of cycloadducts 3 ea, 3 ga, and 3 ac have been analyzed. The twisted naphthalenes arise not only from the overcrowded substituents but also from the contribution of the CH(3)-pi interaction.

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This work describes the syntheses, crystal structures, photophysical properties, and electro-chemical analyses of benzo[k]fluoranthene-based linear acenes, together with ab initio density functional theory computations on them. The molecules were prepared in generally moderate to good yields through Pd-catalyzed cycloadditions between 1,8-diethynylnaphthalene derivatives and aryl iodides. This protocol is simpler and more efficient than conventional methods. The scope and limitations of this reaction were examined. The structures of compounds 4hb, 15ac, 17ab, 19ac, and 24je were determined by X-ray analysis; they are either bent or twisted, rather than planar. The photophysical and electrochemical properties of these cycloadducts were also investigated and compared with computational predictions based on density functional theory.

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