Iron‐Catalysed Carbene Transfer to Isocyanides as a Platform for Heterocycle Synthesis

Abstract

Abstract An iron‐catalysed carbene transfer reaction of diazo compounds to isocyanides has been developed. The resulting ketenimines are trapped in situ with various bisnucleophiles to access a range of densely functionalized heterocycles (pyrimidinones, dihydropyrazolones, 1 H ‐tetrazoles) in a one‐pot process. The electron‐rich Hieber anion ([Fe(CO) 3 NO] − ) facilitates efficient catalytic carbene transfer from acceptor‐type α‐diazo carbonyl compounds to isocyanides, providing a cost‐efficient and benign alternative to similar noble metal‐catalysed processes. Based on DFT calculations a plausible reaction mechanism for activation of the α‐diazo carbonyl carbene precursor and ketenimine formation is provided.