Cope elimination

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The Cope elimination is a name reaction in organic chemistry ; it was named after the American chemist Arthur C. Cope (1909-1966), who wrote several papers on this reaction. It was first described by Leonhard Mamlock and Richard Wolffenstein .

Overview reaction

The Cope elimination is the cleavage of an alkyl radical from a tertiary amine oxide with the formation of the corresponding olefin and secondary hydroxylamine .

Overview reaction of the Cope elimination

The reaction takes place with peroxides, as here with the strong oxidizing agent hydrogen peroxide . The radicals R 1 to R 3 are organic radicals, e.g. B. alkyl radicals .

Reaction mechanism

The reaction proceeds according to the following mechanism. The radicals R 1 , R 2 and R 3 are organic radicals here too . These can be different but also identical.

Cope Elimination M-v4

The tertiary amine 1 is oxidized to an amine oxide 2 by a strong oxidizing agent , here hydrogen peroxide or also by other peroxides . The condition here is that no acidic hydrogen atoms are bonded to the radicals R in the α position . The amine oxide 2 is an assumed transition state which by thermal development from about 100 ° C is converted. The products formed are a terminal olefin 3 or alkene and an amine hydroxide 4 . The amine hydroxide still carries two of the residues of the starting amine. The third remainder is now on the Alken.

See also

Individual evidence

  1. ↑ L. Mamlock, R. Wolffenstein: On the action of hydrogen peroxide on fatty amines . In: Reports of the German Chemical Society . tape 33 , no. 1 , 1900, p. 159–161 , doi : 10.1002 / cber.19000330120 .
  2. ^ AC Cope, ER Trumbull: Olefins from Amines: The Hofmann Elimination Reaction and Amine Oxide Pyrolysis . In: Org. React. tape 11 , 1960, pp. 317-493 .
  3. ↑ AC Cope, TT Foster, PH Towle: Thermal Decomposition of Amine Oxides to Olefins and Dialkylhydroxylamines . In: J. Am. Chem. Soc. tape 71 , no. 12 , 1949, pp. 3929-3934 , doi : 10.1021 / ja01180a014 .
  4. ↑ BP Mundy, MG Ellerd, FG Favaloro, Jr .: Name Reactions and Reagents in organic synthesis . 2nd edition, John Wiley & Sons, Hoboken, New Jersey 2005, ISBN 978-0-471-22854-7 , p. 96.