Catalytic Hydrogenation of N‐protected α‐Amino Acids Using Ruthenium Complexes with Monodentate Phosphine Ligands

Reduction of Carboxylic Acids to Alcohols via Manganese(I) Catalyzed Hydrosilylation

The reduction of carboxylic acids to the respective alcohols, in mild conditions, was achieved using [MnBr(CO)₅] as the catalyst and bench stable PhSiH₃ as the reducing agent. It was shown that the reaction with the earth-abundant metal catalyst could be performed either with a catalyst loading as low as 0.5 mol %, rare with the use of [MnBr(CO)₅], or on a gram scale employing only 1.5 equiv of PhSiH₃, the lowest amount of silane reported to date for this transformation. Kinetic data and control experiments have provided initial insight into the mechanism of the catalytic process, suggesting that it proceeds via the formation of silyl ester intermediates and ligand dissociation to generate a coordinatively unsaturated Mn(I) complex as the active species.

Reaction of H2 with mitochondria-relevant metabolites using a multifunctional molecular catalyst

The Krebs cycle is the fuel/energy source for cellular activity and therefore of paramount importance for oxygen-based life. The cycle occurs in the mitochondrial matrix, where it produces and transfers electrons to generate energy-rich NADH and FADH₂, as well as C₄-, C₅-, and C₆-polycarboxylic acids as energy-poor metabolites. These metabolites are biorenewable resources that represent potential sustainable carbon feedstocks, provided that carbon-hydrogen bonds are restored to these molecules. In the present study, these polycarboxylic acids and other mitochondria-relevant metabolites underwent dehydration (alcohol-to-olefin and/or dehydrative cyclization) and reduction (hydrogenation and hydrogenolysis) to diols or triols upon reaction with H₂, catalyzed by sterically confined iridium-bipyridyl complexes. The investigation of these single-metal site catalysts provides valuable molecular insights into the development of molecular technologies for the reduction and dehydration of highly functionalized carbon resources.