Exhaustive Reduction of Esters Enabled by Nickel Catalysis

We report a one-step procedure to directly reduce unactivated aryl esters into their corresponding tolyl-derivatives. This is achieved by the action of a Ni/NHC catalyst and an organosilane reducing agent that is activated in situ by stoichiometric KOtBu. The resulting conditions provide a direct and efficient alternative to multi-step procedures for this transformation that often require use of hazardous metal hydrides. Applications in the synthesis of –CD3 containing products, derivatization of bioactive molecules, and chemoselective reduction in the presence of other C–O bonds is demonstrated.