Mössbauer and mass spectrometry support for iron( ii ) catalysts in enantioselective C–H activation

A combination of electrospray-ionization mass spectrometry and Mössbauer spectroscopy was used to investigate the species generated in situ in highly enantioselective Fe/NHC-catalyzed C–H alkylations. The findings indicate an organometallic iron( ii )–NHC species to be of key relevance in the asymmetric catalysis.