Chemoselective oxidation of aromatic aldehydes to carboxylic acids: potassium tert -butoxide as an anomalous source of oxygen.

Chemoselective oxidation of aromatic and heteroaromatic aldehydes (>45 examples) to their corresponding carboxylic acids has been developed. Potassium tert -butoxide acts as an oxygen source during this transformation that delivers the corresponding acids without chromatographic purifications. The use of bench-top reagents, operational simplicity, and high level of chemo-selectivity with respect to oxidation of the least preferred aldehyde functionality, in the presence of more susceptible functional groups, are some of the highlights of this strategy.