112440-07-0Relevant articles and documents
TMEDA in iron-catalyzed Kumada coupling: Amine adduct versus homoleptic "ate" complex formation
Bedford, Robin B.,Brenner, Peter B.,Carter, Emma,Cogswell, Paul M.,Haddow, Mairi F.,Harvey, Jeremy N.,Murphy, Damien M.,Nunn, Joshua,Woodall, Christopher H.
supporting information, p. 1804 - 1808 (2014/03/21)
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. Casting iron in catalytic roles: Chelating diamine ligands such as TMEDA are routinely used in iron-catalyzed cross-coupling reactions of aryl Grignard reagents. However, it was found that under catalytically relevant conditions, there is little evidence for their coordination to iron centers; homoleptic anionic organoiron species are produced instead. Copyright
