Ganem oxidation

In organic chemistry, the Ganem oxidation is a name reaction that allows for the preparation of carbonyls from primary or secondary alkyl halides with the use of trialkylamine N-oxides, such as N-methylmorpholine N-oxide or trimethylamine N-oxide.[1]

Ganem oxidation
Named after Bruce Ganem
Reaction type Organic redox reaction

Mechanism

As in other oxoammonium-catalyzed oxidation reactions, the negatively charged oxygen atom of the trialkylamine N-oxide molecule attacks the alkyl halide in a SN2 manner, kicking of the halide as a leaving group. A trialkylamine deprotonates the α-carbon atom, the resulting electron pair shifts onto the oxygen atom, which shifts its own excess electron pair onto the nitrogen atom. This generates the desired carbonyl, as well as the aforementioned trialkylamine. The reaction is an enhancement of the Kornblum oxidation protocol, which was originally developed using dimethyl sulfoxide or pyridine-N-oxide as the nucleophile.

Applications

The Ganem oxidation has been used as an intermediate step in the total synthesis of (−)-okilactomycin, converting a primary alkyl halide into an aldehyde.[2]

References
  1. Godfrey, Alexander G.; Ganem, Bruce (1990-05-30). "Ready oxidation of halides to aldehydes using trimethylamine N-oxide in dimethylsulfoxide". Tetrahedron Letters. 31 (34): 4825–4826. doi:10.1016/S0040-4039(00)97742-6.
  2. Smith, Amos B.; Basu, Kallol; Bosanac, Todd (2007-11-13). "Total Synthesis of (−)-Okilactomycin". Journal of the American Chemical Society. 129 (48): 14872–14874. doi:10.1021/ja077569l. PMID 17997560.


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