Convenient, Mild Catalytic Deprotection of Oximes to Carbonyl Compounds with Hydrogen Peroxide and Iodine Catalyst in Aqueous Acetonitrile

Abstract

A clean, mild, and efficient catalytic deoximation procedure compatible with several common functional groups has been developed using 30% hydrogen peroxide activated by iodine catalyst in aqueous acetonitrile under essentially neutral conditions. The mechanistic features of an iodonium ion–driven nucleophilic cleavage of oximic C[dbnd]N have been revealed.

Keywords:

• Aldehyde
• 30% hydrogen peroxide
• iodine
• ketone
• oxime

ACKNOWLEDGMENTS

S. K. B. thanks the University of Kalyani for financial assistance by way of a research fellowship. Facilities provided by the Department of Science and Technology–Funding for Infrastructure in Science and Technology and the University Grants Commission, Government of India, are also acknowledged.

Notes

^a Reaction conditions: 30% H₂O₂ (0.22 mL) and I₂ (10 mol%) per mmol of substrate in acetonitrile–water (9:1), rt.

^b Isolated yield upon column chromatography; the carbonyl compounds were characterized by their spectral data (FTIR, ¹H NMR), mp, and comparison with authentic sample.^{[ 12 ]}

^c Reaction conditions: 30% H₂O₂ (0.22 ml) and I₂ (10 mol%) per mmol of substrate, MeOH, rt.

^d Reaction conditions: 30% H₂O₂ (0.22 mL) and I₂ (50 mol%), and MeOH (2 mL) per mmol of substrate; 4-hydroxy-3,5-diiodoacetophenone oxime (8a) was formed in a yield of 10%.

^e The low yield of acetophenone is due to concomitant formation of 4-amino-3-iodoacetophenone oxime (9a) in 8% yield.

^f Acetic acid was used as the solvent because of the low solubility of the substrate in aqueous acetonitrile.

^g NR indicates no reaction.