The Babler-Dauben Oxidation is the catalytic chromium-mediated 1,3-oxidative transposition of allylic alcohols.
General features:
1. The reaction produces the desired enone product in high yields, and it doesn’t require air-free conditions nor heating. 2. A common solvent is anhydrous DCM or chloroform. 3. The main drawback is the use of the highly toxic oxidizing agent, PCC. 4. Besides, the Babler-Dauben oxidation of secondary allylic alcohols proves more difficult to control than that of tertiary analogues.
Concerns about the high toxicity and carcinogenicity of the PCC oxidant, as well as the role of chromium(VI) species as environmental pollutants in groundwater, have led to investigations for the replacement of PCC in the reaction. One successful alternative reported by multiple sources involves the use of N-oxoammonium salts derived from TMP:
