Use of Aryliron Complexes [CpFe(CO)₂Ar] as Arylcarbonyl Cation Equivalents in the Reactions with Organolithium Reagents To Yield Ketones

Abstract

Treatment of aryliron complexes [CpFe(CO) 2 Ar] with organolithium reagents RLi in THF affords the corresponding ketones RCOAr. The reaction, wherein the aryliron complexes serve as arylcarbonyl cation equivalents, would begin with nucleophilic addition of RLi to one of the carbonyl ligands to form acyliron [CpFe(CO)(RCO)Ar] without lithiation of the Cp ring. Dicarbonylcyclopentadienylorganoiron complexes [CpFe-(CO) 2 R] represent an important class of organometallic compounds due to their rich coordination chemistry. 1 The corresponding aryliron complexes [CpFe(CO ) 2 Ar] are fundamental 18-electron arylmetals, and several reliable methods for the synthesis of the aryliron complexes have been reported. 2 On the other hand, the chemical reactivity of the aryliron complexes has not been well investigated. [3][4][5][6][7][8] Thanks to the ubiquity and abundance of iron as a transition metal, we have envisioned that [CpFe(CO) 2 Ar] would serve as interesting arylating agents in organic synthesis and have been studying the reactivity and utility of [CpFe(CO) 2 Ar]. 2e,2f