Simplified Procedure for TEMPO-Catalyzed Oxidation: Selective Oxidation of Alcohols, α-Hydroxy Esters, and Amides Using TEMPO and Calcium Hypochlorite

Abstract

A wide range of primary and secondary multifunctional alcohols, α-hydroxyamides, and α-hydroxyesters were oxidized to their corresponding aldehydes, ketones, α-ketoamides, and α-ketoesters under mild reaction conditions using 2,2,6,6-tetramethylpiperidine-1-oxyl as a catalyst with calcium hypochlorite as an oxidant [TEMPO-Ca(OCl)₂]. This simplified method does not require any transition metals, acids, or bases and demonstrates controlled and selective oxidation of structurally diverse alcohols, affording moderate to excellent yields at room temperature.

GRAPHICAL ABSTRACT

Keywords:

• Alcohol
• calcium hypochlorite
• oxidation
• TEMPO

ACKNOWLEDGMENTS

Funding from the Department of Science and Technology (DST), Government of India is gratefully acknowledged. The authors thank the Sophisticated Analytical Instrumentation Facility (SAIF), Indian Institute of Technology Madras, for NMR analysis. One of the authors (S. S.) is grateful to the Council of Scientific and Industrial Research, New Delhi, for the fellowship.

Notes

^a Structures of the products were determined from their spectroscopic (IR, ¹H and ¹³C NMR, and MS) data.

^b 1.5 equiv. calcium hypochlorite was used.

^c Dichloromethane and acetonitrile in a 1:2 ratio were used as solvent.

^a Structures of the products were determined from their spectroscopic data (IR, ¹H and ¹³C NMR, and MS).

^b Acetonitrile was used as solvent.

^c Tetrahedrofuran was used as solvent.

^a Structures of the products were determined from their spectroscopic (IR, ¹H and ¹³C NMR, and MS) data.