The reduction of carboxylic acids to the respective alcohols, in mild conditions, was achieved using [MnBr(CO) 5 ] as the catalyst and bench stable PhSiH 3 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 PhSiH 3 , 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.

The development of sustainable synthetic routes to access valuable oxazolidinones via CO 2 fixation is an active research area, and the aziridine/carbon dioxide coupling has aroused a considerable interest. This reaction features a high activation barrier and thus requires a catalytic system, and may present some other critical issues. Here, the straightforward gram-scale synthesis of a series of 5-aryl-2-oxazolidinones was developed at ambient temperature and atmospheric CO 2 pressure, in the absence of any catalyst/co-catalyst. The key to this innovative procedure consists in the direct transfer of the pre-formed amine/CO 2 adduct (carbamate) to common aziridine precursors (dimethylsulfonium salts), replacing the classical sequential addition of amine (intermediate isolation of aziridine) and then CO 2. The reaction mechanism was investigated by NMR spectroscopy and DFT calculations applied to model cases.

This study presents the use of MnBr(CO)5 for the selective conversion of silanes to silanols with water as an oxidant generating valuable hydrogen as the only by-product.