Rimoldi, I.

New J. Chem. 2018, 42, 18773-18776, 10.1039/C8NJ04558E

The imine reductase formed by the (R)-CAMPY ligand bound to the S112M Sav mutant showed an 83% ee in the asymmetric transfer hydrogenation of 6,7-dimethoxy-1-methyl-3,4-dihydroisoquinoline.

Pellegrino, S.; Rimoldi, I.

Inorg. Chem. 2021, 60, 2976-2982, 10.1021/acs.inorgchem.0c02969

Based on the supramolecular interaction between vancomycin (Van), an antibiotic glycopeptide, and D-Ala-D-Ala (DADA) dipeptides, a novel class of artificial metalloenzymes was synthesized and characterized. The presence of an iridium(III) ligand at the N-terminus of DADA allowed the use of the metalloenzyme as a catalyst in the asymmetric transfer hydrogenation of cyclic imines. In particular, the type of link between DADA and the metal-chelating moiety was found to be fundamental for inducing asymmetry in the reaction outcome, as highlighted by both computational studies and catalytic results. Using the [IrCp*(m-I)Cl]Cl ⊂ Van complex in 0.1 M CH3COONa buffer at pH 5, a significant 70% (S) e.e. was obtained in the reduction of quinaldine B.

Arseniyadis, S.; Campagne, J.; Smietana, M.

Chem. Eur. J. 2020, 26, 3519-3523, 10.1002/chem.202000516

While artificial cyclases hold great promise in chemical synthesis, this work presents the first example of a DNA-catalyzed inverse electron-demand hetero-Diels–Alder (IEDHDA) between dihydrofuran and various α,β-unsaturated acyl imidazoles. The resulting fused bicyclic O,O-acetals containing three contiguous stereogenic centers are obtained in high yields (up to 99 %) and excellent diastereo- (up to >99:1 dr) and enantioselectivities (up to 95 % ee) using a low catalyst loading. Most importantly, these results show that the concept of DNA-based asymmetric catalysis can be expanded to new synthetic transformations offering an efficient, sustainable, and highly selective tool for the construction of chiral building blocks.

Rimoldi, I.

ChemCatChem 2016, 8, 1665-1670, 10.1002/cctc.201600116

The possibility of obtaining an efficient artificial imine reductase was investigated by introducing a chiral cofactor into artificial metalloenzymes based on biotin–streptavidin technology. In particular, a chiral biotinylated 1,3‐diamine ligand in coordination with iridium(III) complex was developed. Optimized chemogenetic studies afforded positive results in the stereoselective reduction of a cyclic imine, the salsolidine precursor, as a standard substrate with access to both enantiomers. Various factors such as pH, temperature, number of binding sites, and steric hindrance of the catalytic moiety have been proved to affect both efficiency and enantioselectivity, underlining the great flexibility of this system in comparison with the achiral system. Computational studies were also performed to explain how the metal configuration, in the proposed system, might affect the observed stereochemical outcome.

Case, M.A.

Acc. Chem. Res. 2004, 10.1021/ar960245+

Metal-assembled parallel helix-bundle proteins have been used to investigate electron transfer through α-helical structures. Fermi Golden Rule distance dependence of electron transfer rates was established in a family of designed metalloproteins, and the contribution of intrahelical hydrogen bonding to the matrix tunneling element was explored. The first steps toward the design of functional proteins using dynamic combinatorial assembly of α-helical structural elements are described.