Sulfone‐Linked Paracyclophanes via Macrocyclic Aromatic Thioethers: Synthetic and Structural Investigations

Reaction of 4,4′‐sulfonylbis(benzenethiol) with 4,4′‐dichlorodiphenylsulfone under pseudo‐high‐dilution conditions leads to macrocyclic thioethersulfones [‐S‐Ar‐SO 2 ‐Ar‐] n (Ar=1,4‐phenylene). These include a highly strained [1+1] cyclodimer ( n =2), a cyclotrimer resulting from thioether‐exchange reactions, and a [2+2] cyclotetramer which can adopt two entirely different conformations in the crystalline state, one having molecular D 2d (“tennis‐ball‐seam”) symmetry. The same type of reaction is successful using 4,4′‐thiobis(benzenethiol) instead of 4,4′‐sulfonylbis(benzenethiol) and affords macrocycles with a higher ratio of thioether to sulfone linkages. Exhaustive oxidation of macrocyclic thioethersulfones with hydrogen peroxide affords a series of sulfone‐linked paracyclophanes, [‐Ar‐SO 2 ‐] 4 , [‐Ar‐SO 2 ‐] 6 , [‐Ar‐SO 2 ‐] 8 and [‐Ar‐SO 2 ‐] 12 . Single crystal X‐ray analysis reveals [Ar‐SO 2 ‐] 4 to be a near‐perfect square box, whilst the cyclic hexamer [‐Ar‐SO 2 ‐] 6 adopts a much more irregular conformation, and [‐Ar‐SO 2 ‐] 8 displays a “double‐box” structure clearly related to that of [Ar‐SO 2 ‐] 4 .