A Safe-at-Home Solventless Air Oxidation of Benzoin by Microwave

Oxidations make up an important class of functional group transformations in organic chemistry, allowing access to aldehydes, ketones, and carboxylic acids from alcohols and even alkenes. Traditionally, chromium VI (hexavalent chromium)-based oxidants serve as robust but nonselective oxidants. Nitric acid and potassium permanganate also serve as more robust and, therefore, even less selective oxidants. Interestingly, many lab curricula continue to focus on oxidations using harsher conditions, while many oxidations with bleach and even air under catalytic conditions are available. We report a novel, safe-at-home oxidation with readily available sodium carbonate (and readily available oxygen) and benzoin from previously reported work, with a mechanism that likely mimics vitamin C activity. While the reaction in the laboratory could easily be replaced by other mild oxidations, this report offers a rare organic chemistry experiment that could be performed and observed at home despite the limits of characterization available to students outside of a laboratory setting. In the lab, the simple base-catalyzed formation of the dienolate offers an opportunity for students to think about screening and optimizing the reaction conditions.