Elevated Catalytic Activity of Ruthenium(II)–Porphyrin‐Catalyzed Carbene/Nitrene Transfer and Insertion Reactions with N‐Heterocyclic Carbene Ligands

Abstract

Bis(NHC)ruthenium(II)–porphyrin complexes were designed, synthesized, and characterized. Owing to the strong donor strength of axial NHC ligands in stabilizing the trans MCRR′/MNR moiety, these complexes showed unprecedently high catalytic activity towards alkene cyclopropanation, carbene CH, NH, SH, and OH insertion, alkene aziridination, and nitrene CH insertion with turnover frequencies up to 1950 min−1. The use of chiral [Ru(D4‐Por)(BIMe)2] (1 g) as a catalyst led to highly enantioselective carbene/nitrene transfer and insertion reactions with up to 98 % ee. Carbene modification of the N terminus of peptides at 37 °C was possible. DFT calculations revealed that the trans axial NHC ligand facilitates the decomposition of diazo compounds by stabilizing the metal–carbene reaction intermediate.

Abiological catalysis by artificial haem proteins containing noble metals in place of iron

“…Because the repertoire of reactions catalysed by free metal-porphyrin complexes of Ru (ref. 15), Rh (ref. 16) and Ir (ref.…”

Organometallic 3d transition metal NHC complexes in oxidation catalysis

“…146 Transition metal catalysed direct amination of alkanes via C-H activation is receiving attention for being able to overcome certain challenges such as substrate limitation and undesired product regioselectivity. 147 In this context and inspired by the catalytic efficiency of noble metal based ruthenium(II) porphyrins, 148 an iron(III) porphyrin complex, bearing axial imidazole ligands, is introduced (Scheme 12, 23). Compound 23 provides catalytic access to a wide range of alicyclic amines via an intramolecular C(sp 3 )-H-amination of alkyl azides (Scheme 12).…”

“…In this context and inspired by the catalytic efficiency of noble metal based ruthenium( ii ) porphyrins, 148 an iron( iii ) porphyrin complex, bearing axial imidazole ligands, is introduced (Scheme 12, 23 ). Compound 23 provides catalytic access to a wide range of alicyclic amines via an intramolecular C(sp 3 )–H-amination of alkyl azides (Scheme 12).…”

N‐Heterocyclic Carbenes: Molecular Porters of Surface Mounted Ru‐Porphyrins

“…Inspired by catalytically active porphyrin Ru‐NHC compounds, [12] we recently used an NHC ligand to functionalise Ru centres in porphyrins on a silver surface [13] . The modular construction of such interfaces worked remarkably well: the NHC was found to selectively ligate to the Ru centre of the pre‐assembled porphyrins on Ag(111) without disrupting their self‐assembly.…”