Functionalization of N,N‑Dialkylferrocene­sulfonamides toward Substituted Derivatives

Despite the well-established pharmacological properties of aromatic sulfonamides and the interest of introducing ferrocene into drugs, ferrocene sulfonamides have scarcely been studied. General synthetic methods using lithium bases to perform sulfonamide-directed deprotolithiation or the “halogen dance” reaction are here reported for the functionalization of N,N-dialkylferrocene­sulfonamides toward various polysubstituted derivatives. Postfunctionalization of the ferrocenyl iodides by cross-coupling and lithium/iodine exchange reactions were also considered. Finally, the ligand behavior of new ferrocene phosphines in palladium-catalyzed coupling reactions was studied, and the reaction outcomes are viewed in light of DFT calculations.