Tishchenko reaction
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The Tishchenko reaction is a chemical reaction that involves disproportionation of an aldehyde lacking a hydrogen atom in the alpha position in the presence of an alkoxide.[#endnote_1] The reaction product is an ester. Catalysts are aluminium alkoxydes or sodium alkoxides. Benzaldehyde reacts with sodium benzyloxide (generated from sodium and benzyl alcohol) to benzyl benzoate.[#endnote_2]
Paraformaldehyde reacts with boric acid to methyl formate.[#endnote_3] The key step in the reaction mechanism for this reaction is a 1,3-hydride shift in the hemiacetal intermediate formed from two successive nucleophilic addition reactions, the first one from the catalyst. The hydride shift regenerates the alkoxide catalyst.
In the related Cannizzaro reaction the base is sodium hydroxide and then the oxidation product is a carboxylic acid and the reduction product is an alcohol.
Related reactions
- Aldol-Tishchenko reaction
- Baylis-Hillman reaction
- Cannizzaro reaction
- Meerwein-Ponndorf-Verley Reduction
- Oppenauer Oxidation
References
- ↑ V. Tishchenko, J. Russ. Phys. Chem. Soc. 1906, 38, 355, 482, 540, 547.
- ↑ O. Kamm and W. F. Kamm Organic Syntheses, Coll. Vol. 1, p.104; Vol. 2, p.5 [Online article]
- ↑ Boric acid catalyzed Tishchenko reactions. Paul R. Stapp, J. Org. Chem. 1973, 38(7), 1433-1434. [Abstract]
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