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Clemmensen reduction

The Clemmensen reduction is a chemical reaction described as a reduction of ketones (or aldehydes) to alkanes using zinc amalgam and hydrochloric acid.[1][2][3] This reaction is named after Erik Christian Clemmensen, an Danish-American chemist.[4]

Several reviews have been published.[5][6][7][8]

The Clemmensen reduction is particularly effective at reducing aryl-alkyl ketones.[9][10] With aliphatic or acyclic ketones, zinc metal reduction is much more effective.[11]

The substrate must be stable in the strongly acidic conditions of the Clemmensen reduction. Acid sensitive substrates should use the Wolff-Kishner reduction, which utilizes strongly basic conditions. As a result of Clemmensen Reduction, the carbon of the carbonyl group involved is converted from Sp2 hybridisation to Sp3 hybridisation. The oxygen atom is lost in the form of one molecule of water.


  1. ^ Clemmensen, E. Ber. 1913, 46, 1837.
  2. ^ Clemmensen, E. Ber. 1914, 47, 51.
  3. ^ Clemmensen, E. Ber. 1914, 47, 681.
  4. ^ Biographies of Chemists, accessed 6 Feb 2007.
  5. ^ Martin, E. L. Org. React. 1942, 1, 155. (Review)
  6. ^ Buchanan, J. G. St. C.; Woodgate, P. D. Quart. Rev. 1969, 23, 522. (Review)
  7. ^ Vedejs, E. Org. React. 1975, 22, 401. (Review)
  8. ^ Yamamura, S.; Nishiyama, S. Comp. Org. Syn. 1991, 8, 309-313.(Review)
  9. ^ Organic Syntheses, γ-Phenylbutyric acid, Coll. Vol. 2, p.499 (1943); Vol. 15, p.64 (1935).
  10. ^ Organic Syntheses, Creosol, Coll. Vol. 4, p.203 (1963); Vol. 33, p.17 (1953).
  11. ^ Organic Syntheses, Modified Clemmensen Reduction: Cholestane, Coll. Vol. 6, p.289 (1988); Vol. 53, p.86 (1973).

See also

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Clemmensen_reduction". A list of authors is available in Wikipedia.
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