Parikh-Doering oxidation
The Parikh-Doering oxidation is a name reaction in organic chemistry that was named after its discoverers Jekishan R. Parikh and William v. E. Doering was named.
With the Parikh-Doering oxidation, primary and secondary alcohols are converted into aldehydes or ketones . As with the Swern oxidation, activated dimethyl sulfoxide (DMSO) is used as the oxidizing agent. For activation , however, a serving adduct of sulfur trioxide and pyridine in the presence of triethylamine .
The reaction can be carried out under mild conditions, usually at 0 ° C.
Reaction mechanism
In the first step, the dimethyl sulfoxide (DMSO) is activated using sulfur trioxide .
The activated DMSO is attacked nucleophilically by the alcohol. The intermediate product thus formed is now deprotonated by pyridine . In addition, sulphate is split off by a rearrangement , which is separated off in a complex with the pyridinium. The alkoxysulfonium ion is then deprotonated by triethylamine to form the sulfonium ylide. The subsequent β-elimination via a cyclic transition state leads to the cleavage of dimethyl sulfide, so that the end product, the ketone or aldehyde, is formed.
See also
Individual evidence
- ^ G. Tojo, M. Fernández: Oxidation of alcohols to aldehydes and ketones , 2nd edition, p. 125, Springer Verlag, Berlin, ISBN 0-387-23607-4 .
- ↑ JR Parikh and W. v. E. Doering: Sulfur Trioxide in the Oxidation of Alcohols by Dimethyl Sulfoxide , in: J. Am. Chem. Soc. 1967 , 89 , 5505-5507; doi : 10.1021 / ja00997a067 .
literature
- Organic Syntheses Based on Name Reactions, A. Hassner & I. Namboothiri, 3rd edition, Elsevier
- Oxidation of Alcohols to Aldehydes and Ketones, Gabriel Tojo and Marcos Fernandez, 2006, Springer Science + Business Media, Inc.