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TMEDA in Iron‐Catalyzed Kumada Coupling: Amine Adduct versus Homoleptic “ate” Complex Formation |
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| Authors: | Prof. Dr. Robin B. Bedford Dr. Peter B. Brenner Dr. Emma Carter Paul M. Cogswell Dr. Mairi F. Haddow Prof. Dr. Jeremy N. Harvey Prof. Dr. Damien M. Murphy Joshua Nunn Dr. Christopher H. Woodall |
| Affiliation: | 1. School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS (UK);2. School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3TB (UK) |
| Abstract: | The reactions of iron chlorides with mesityl Grignard reagents and tetramethylethylenediamine (TMEDA) under catalytically relevant conditions tend to yield the homoleptic “ate” complex [Fe(mes)3]? (mes=mesityl) rather than adducts of the diamine, and it is this ate complex that accounts for the catalytic activity. Both [Fe(mes)3]? and the related complex [Fe(Bn)3]? (Bn=benzyl) react faster with representative electrophiles than the equivalent neutral [FeR2(TMEDA)] complexes. FeI species are observed under catalytically relevant conditions with both benzyl and smaller aryl Grignard reagents. The X‐ray structures of [Fe(Bn)3]? and [Fe(Bn)4]? were determined; [Fe(Bn)4]? is the first homoleptic σ‐hydrocarbyl FeIII complex that has been structurally characterized. |
| Keywords: | catalysis cross‐coupling Grignard reagents iron |