Aminomethylations of electron-deficient compounds-bringing iron photoredox catalysis into play.

The α-functionalisation of -containing compounds is an area of broad interest in synthetic chemistry due to their presence in biologically active substances among others. Visible light-induced generation of nucleophilic α-aminoalkyl radicals as reactive intermediates that can be trapped by electron-deficient alkenes presents an attractive and mild approach to achieve said functionalisation. In this work, [Fe(iii)(phtmeimb)]PF (phtmeimb = phenyl(tris(3-methylimidazol-2-ylidene))borate), an N-heterocyclic carbene (NHC) complex based on Earth-abundant iron, was used as photoredox catalyst to efficiently drive the formation of α-aminoalkyl radicals from a range of different α-trimethylsilylamines and their subsequent addition to a number of electron-deficient alkenes under green light irradiation.

Photoredox catalysis consecutive LMCT- and MLCT-excitation of an Fe(iii/ii)-N-heterocyclic carbene complex.

Fe-N-heterocyclic carbene (NHC) complexes attract increasing attention as photosensitisers and photoredox catalysts. Such applications generally rely on sufficiently long excited state lifetimes and efficient bimolecular quenching, which leads to there being few examples of successful usage of Fe-NHC complexes to date. Here, we have employed [Fe(iii)(btz)] (btz = (3,3'-dimethyl-1,1'-bis(-tolyl)-4,4'-bis(1,2,3-triazol-5-ylidene))) in the addition of alkyl halides to alkenes and alkynes visible light-mediated atom transfer radical addition (ATRA).