Saegusa oxidation

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The Saegusa Oxidation (also known as Saegusa-Ito Oxidation or Saegusa-Ito Reaction ) is a name reaction in organic chemistry . These were discovered in 1978 by the Japanese chemists Takeo Saegusa and Yoshihiko Ito (1937-2006). This synthesis produces an ( E ) -configured α, β-unsaturated aldehyde or a ketone . According to this method z. B. produce methyl vinyl ketone or chalcone .

Overview reaction

With the Saegusa oxidation, saturated aldehydes can specifically oxidize in the α, β-position , so that α, β-unsaturated aldehydes with ( E ) -configuration are formed:

Production of α, β-unsaturated aldehydes

Here, R can stand for a hydrogen atom, an alkyl radical or an aryl radical (e.g. phenyl radical ). Saturated ketones react analogously to form α, β-unsaturated ( E ) ketones (R 1 , R 2 = H, alkyl, aryl):

Production of α, β-unsaturated aldehydes

Reaction mechanism

A possible reaction mechanism will be explained using the example of the oxidation of aldehyde 1 .

Saegusa Oxidation Reaction Mechanism V4.svg

First, 1 is reacted with trimethylsilyl chloride ( TMSCl ) and a base (e.g. triethylamine ), whereby the enol ether 2 is formed. Then 2 is reacted with palladium (II) acetate, the palladium complex 3 being formed. By shifting a trimethylsilyl group, the minor valence bond of 3 becomes a covalent bond, thus creating the ketone 4 . By splitting off the palladium residue and a proton , the α, β-unsaturated aldehyde 5 is now formed . The palladium residue can now be worked up again with benzoquinones so that the reaction proceeds economically.

Synthesis of drugs

In 2006 Tohru Fukuyama used Saegusa oxidation to produce the drug morphine , a pain reliever. In addition, Saegusa oxidation is used in the Yong-Qiang-Tu synthesis. This reaction produces the drug galantamine used to treat dementia .

Individual evidence

  1. ↑ Masahiro Murakami: Yoshihiko Ito (1937-2006) . In: Angewandte Chemie International Edition . 46, No. 18, 2007, p. 3176. doi : 10.1002 / anie.200701275 .
  2. ↑ a b c d L. Kürti, B. Czako (ed.): Strategic Applications of named reactions in organic synthesis , Elsevier Academic Press, China 2005, ISBN 978-0-12-369483-6 , p. 390.
  3. ↑ Z. Wang (Ed.): Comprehensive Organic Name Reactions and Reagents, 3 Volume Set . John Wiley & Sons, Hoboken, NJ 2009, ISBN 978-0-471-70450-8 , p. 2462.
  4. ↑ Y. Ito, T. Hirao, T. Saegusa: Synthesis of α, β- unsaturated carbonyl compounds by palladium (II) -catalyzed dehydrosilylation of silyl enol ethers . In: Journal of Organic Chemistry . tape 43 , no. 5 , 1978, p. 1011-1013 , doi : 10.1002 / cber.190403703118 .
  5. ↑ a b c Z. Wang (Ed.): Comprehensive Organic Name Reactions and Reagents, 3 Volume Set . John Wiley & Sons, Hoboken, NJ 2009, ISBN 978-0-471-70450-8 , p. 2463.
  6. ^ A b B. P. Mundy, MG Ellerd, FG Favaloro Jr. (Ed.): Name Reactions and Reagents in Organic Synthesis, Secound Edition . John Wiley & Sons, Hoboken, NJ 2005, ISBN 0-471-22854-0 , p. 566.
  7. ↑ K. Uchida, S. Yokoshima, T. Kan, T. Fukuyama: Total Synthesis of (±) -Morphine . In: Organic Letters . tape 8 , 2006, p. 5311-5313 , doi : 10.1021 / ol062112m .
  8. ↑ X.-D. Hu, YQ Tu, E. Zhang, S. Gao, S. Wang, A. Wang, C.-A. Fan, M. Wang ,: Total Synthesis of (±) -Galathamine . In: Organic Letters . tape 8 , 2006, p. 1824 , doi : 10.1021 / ol060339b .