Meerwein–Ponndorf–Verley reduction
The Meerwein-Ponndorf-Verley Reduction in organic chemistry is the reduction of ketones to secondary alcohols with aluminumisopropylate catalysis in isopropanol solution [1][2].
First the carbonyl-oxygen coordinates to the aluminumisopropylate 2. This makes the carbonyl-carbon even more positive. In the next step the hydride attacks the carbonyl-carbon and a 6-membered cyclic transition state is formed. After the hydride shift the alcoholate of the desired alcohol 5 and acetone 6 remain. The alcoholate reacts with another isopropanol molecule to form the alcohol 3 and recover the Aluminumisopropylate.
All of these reactions are reversible, and complete conversion can be achieved by employing excess alcohol as the reaction solvent or by removal of acetone from the reaction mixture by distillation.
The same process in the opposite direction is called Oppenauer oxidation.
References
- Hans Meerwein, Rudolf Schmidt (1924). Justus Liebigs Annalen der Chemie. 444 (1): 221–238. doi:10.1002/jlac.19254440112.
{{cite journal}}: Missing or empty|title=(help) - Wolfgang Ponndorf (1926). "Der reversible Austausch der Oxydationsstufen zwischen Aldehyden oder Ketonen einerseits und primären oder sekundären Alkoholen anderseits". Angewandte Chemie. 39 (5): 138–143. doi:10.1002/ange.19260390504.
- Verley, A., (1925). Bull. Soc. Chim. Fr. 37: 537.
{{cite journal}}: Missing or empty|title=(help)CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link) - L. M. Jackman; J. A. Mills (1949). "Mechanism of the Meerwein–Ponndorf Reduction". Nature. 164: 789–790. doi:10.1038/164789a0.
{{cite journal}}: CS1 maint: multiple names: authors list (link)