8‐Aminoquinoline‐Assisted Synthesis and Crystal Structure Studies of Ferrocenyl Aryl Sulfones.

A copper‐catalyzed 8‐aminoquinoline‐directed oxidative cross‐coupling of the C−H bond of ferrocene with sodium arylsulfinates has been achieved. The robust copper catalyst tolerates a range of methyl, tert‐butyl, bromo, chloro, iodo and nitro functional groups in the phenyl ring, and set the stage for the synthesis of substituted ferrocene sulfones. Furthermore, X‐ray crystal structure study on several ferrocenyl sulfones reveals the tetrahedral geometry around sulfur; interestingly, the O‐S‐O angle is larger than the electropositive substituent C‐S‐C angle which could be explained by Bent's rule. Further, unusual intramolecular O(S)⋅⋅⋅N(amide) short contacts (2.925–3) and O(S)⋅⋅⋅C=O were also noticed in ferrocenyl sulfones. [ABSTRACT FROM AUTHOR]