Catalytic hydroboration of ketones using Mn(CO)5Br and Mn2(CO)10

The commercially available and easy to handle manganese complexes Mn(CO)5Br and Mn2(CO)10 were found to effectively catalyze the hydroboration of ketones under mild conditions providing after hydrolysis secondary alcohols. These simple catalysts showed great tolerance to different functional groups. Moreover, the reaction proceeded with high chemoselectivity toward C=O in the presence of ester, nitrile, nitro group, or double C=C bond. The proposed procedure enables fast and efficient synthesis of O-borylated products, which are easily hydrolyzed in one-pot manner to various aryl and alkyl alcohols (even unsaturated ones) with excellent yields. Therefore, the developed procedure is very competitive to other Mn catalytic systems, which required long preparation steps, application of structurally and electronically advanced ligands, and oxygen and moisture free conditions.