A Practical Oxidation Experiment for Undergraduate Students: Bobbitt’s Salt as a “Green” Alternative

Abstract

Oxidation reactions are critical components of the synthetic toolbox taught to undergraduate students during introductory organic chemistry courses. However, the oxidation reactions discussed in the undergraduate curriculum are often outdated as many organic chemistry textbooks emphasize chromium-based oxidants that are no longer in regular use by practitioners, which may limit an instructor’s time to allocate to discussion of other oxidants. Further, laboratory courses have since either removed oxidation experiments or replaced them with oxidative processes not discussed in lectures, thus leading to a disconnect between the two learning settings. As part of an effort to bridge this divide and modernize the oxidation reactions discussed in our curricula, we have developed a new laboratory experiment that uses a commercially available oxoammonium salt (Bobbitt’s salt) to cleanly oxidize cinnamyl alcohol to cinnamaldehyde. In addition to being a safe, convenient, colorimetric, and “green oxidant” suitable for use in the undergraduate teaching laboratory, the hydride-transfer mechanism allows for overlap with key course concepts presented in both introductory and advanced lecture courses. The procedure is well-suited for small and large organic I, II, or advanced laboratory sections alike and can be completed within a standard 3–4 h laboratory period. Aside from exposing students to a modern green oxidation protocol, the experiment contains expanded opportunities for interpretation of 1H NMR, 13C NMR, and IR spectra. An optional addendum for advanced students involving Hammett correlations was also developed.