Aerobic Alcohol Oxidation Using a Copper(I)/TEMPO Catalyst System: A Green, Catalytic Oxidation Reaction for the Undergraduate Organic Chemistry Laboratory

Modern undergraduate organic chemistry textbooks provide detailed discussion of stoichiometric Cr- and Mn-based reagents for the oxidation of alcohols, yet the use of such oxidants in instructional and research laboratories, as well as industrial chemistry, is increasingly avoided. This work describes a laboratory exercise that uses ambient air as the source of oxidant and a readily available Cu-I/TEMPO catalyst system to convert benzyl alcohols to the corresponding aldehydes in standard glassware at room temperature. The procedure is well suited for a high-enrollment undergraduate course, and the complete exercise fits easily within a 3-h lab period. The structures of the organic starting materials and products are determined by NMR spectroscopy and EI-MS. The protocol is adapted from the contemporary research literature and provides students with practical experience of a modern, "green" oxidation method. In addition to the practical aspects, the experiment encourages student discussion and exploration of transition-metal-catalyzed reactions, a topic that is underrepresented in the contemporary undergraduate organic chemistry curriculum.