Mechanistic Aspects of Formation of Chiral Ruthenium Hydride Complexes from 16‐Electron Ruthenium Amide Complexes and Formic Acid: Facile Reversible Decarboxylation and Carboxylation

The 16‐electron amide complex, Ru[( R,R )‐TsNCHPhCHPhNH](η 6 ‐ p ‐cymene) (Ts= p ‐toluenesulfonyl, Ph=C 6 H 5 ) readily reacts with formic acid to give the corresponding formate complex, which subsequently undergoes decarboxylation leading to the hydride complex with release of CO 2 . The reaction of this hydride complex with CO 2 under mild reaction conditions, a pressure of 10 atm and even at −78 °C, proceeds rapidly to give the corresponding formate complex almost quantitatively. Thus, the reversible decarboxylation and carboxylation takes place with or without the aid of a metal‐NH bifunctional effect of the Ru complexes.