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Abstract:
Definition and nomenclature of cycloarenes, a new class of aromatic compounds, are discussed. Cyclo[d.e.d.e.d.e.d.e.d.e.d.e]dodecakisbenzene (“kekulene”, 1) has been synthesized as the first representative of cycloarenes. – From the dithiaphane 11 by double sulfur extrusion, either photochemically or by pyrolysis of disulfone 12, the carbocyclic system 13 was formed which by dehydrogenation yielded 14. By Stevens rearrangement of 11 followed by elimination the phanediene 15 was obtained which was dehydrogenated to 18. From 15 by photo‐cyclodehydrogenation in excellent yield the octahydrokekulene 19 was obtained. The different reactivity of 15 and 18 in the photo‐cyclodehydrogenation is discussed in terms of electronic and steric effects. Dehydrogenation of 19 yielded 1.