Nucleophilic Aromatic Substitution Reactions in Cyclopentadienyliron Complexes of Chloroarenes and Nitroarenes

Abstract

n⁶-Chloroarene or nitroarene-n⁵-cyclopentadienyliron hexafluorophosphates react readily with CF₃CH₂OH/K₂CO₃ or with piperidine or piperazine to give nucleophilic aromatic substitutions with Cl or NO₂ as the leaving group, further demonstrating an activation for S_NAr reactions by complexation to the CpFe⁺ moiety. Similar nucleophilic aromatic substitution reactions can also occur with carbanion-enolate anion nucleophiles derived from acetylacetone, diethyl malonate and ethyl acetoacetate, leading to the formation of C-C bonds. Pyrolytic sublimation of these S_NAr reaction products could liberate the free substituted arene ligands, such as the synthetically useful diethyl phenylmalonate and ethyl α-phenylacetoacetate.