Pfitzner-Moffatt oxidation

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The Pfitzner-Moffatt oxidation , often also simply Moffat oxidation , is a mild oxidation method that converts primary and secondary alcohols with N , N ′ -dicyclohexylcarbodiimide (DCC) and dimethyl sulfoxide (DMSO) into the respective aldehydes or ketones . What is special here is that the oxidation stops in the case of primary alcohols after the first oxidation step and does not proceed to the carboxylic acid , as is the case with conventional treatment with oxidizing agents .

Overview of the Pfitzner-Moffatt reaction

Similar reactions are the Swern oxidation (higher yield with fewer byproducts), the Dess-Martin oxidation , the Julia oxidation or the oxidation with pyridinium chlorochromate .

Further work was also published.

Reaction mechanism

In the first step, the dimethyl sulfoxide (DMSO ) is activated with N , N ′ -dicyclohexylcarbodiimide (DCC).

Activation of the DMSO

The activated DMSO is now attacked nucleophilically by the alcohol. Rearrangements and cleavage result in a reactive intermediate, a mesomer- stabilized alkoxysulfonium ylide . A β-elimination with a cyclic transition state with elimination of dimethyl sulfide leads to the end product.

Pfitzner-Moffatt reaction mechanism

literature

  • Strategic Applications of Named Reactions in Organic Synthesis, László Kürti & Barbara Czakó, 2005, Elsevier Academic Press

Individual evidence

  1. ↑ KE Pfitzner, JG Moffatt, A New and Selective Oxidation of Alcohols , J. Am. Chem. Soc. , 85 (1963) p. 3027.
  2. ↑ JG Moffatt: Sulfoxide-Carbodiimide and Related Oxidations in: Oxidation Vol. 2, RL Augustine, DJ Trecker, editor. (Dekker, New York, 1971) pp. 1-64.
  3. ↑ TT Tidwell, Org.React. 1990 , 39 , 297-572 (review).
  4. ^ TV Lee, Comp. Org. Syn. 1991 , 7 , 291-303 (review article).