A sustainable mechanochemical approach to the selective oxidation of benzylic alcohols

The growing interest in sustainable oxidation processes arises from the need to reduce the environmental impact of this kind of reaction [1]. Mechanochemistry has emerged as a powerful tool for conducting reactions in a more sustainable manner [2] and it is increasingly recognized as an innovative approach for catalyst activation [3] and chemical synthesis [4]. This work developed a new sustainable oxidation method for the selective conversion of benzylic alcohols into aldehydes via a solvent-free mechanochemical approach. The most effective catalyst system consists of copper-supported on an inorganic material in combination with TEMPO. As reported in figure 1, this methodology enables the oxidation of a variety of benzylic alcohols to their corresponding carbonyl compounds. The presence and nature of substituents on the aromatic ring influence the reaction yield. A green chemistry assessment [5,6,7] demonstrates that this method is more sustainable than the corresponding solution-based process. Additionally, it is less energy and time intensive while providing improved selectivity.