Blaise ketone synthesis

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Blaise ketone synthesis
Named after Edmond Blaise
Reaction type Coupling reaction

The Blaise ketone synthesis (named after Edmond Blaise) is the

organozinc compounds to give ketones.[1][2]

The Blaise ketone synthesis
The Blaise ketone synthesis

The reaction was claimed to bring excellent yields by Blaise, however, investigators failed to obtain better than moderate yields (50%).[3][4] Thus, the reaction is particularly ineffective in forming ketones from acyl chlorides. The reaction also works with

organocuprates.[5][6] Reviews have been written.[7][8]

Reaction mechanism

The mechanism is sampled from the proposed mechanism for

organocadmium compounds, given that the mechanisms are identical to one another the proposed mechanism for the reaction is the same as the one for organocadmium compounds[9][10]
.

Proposed mechanism for the Blaise ketone synthesis.
Proposed mechanism for the Blaise ketone synthesis.

After the oxygen forms a bond with the organozinc compound, R’ shifts to the carbonyl carbon, having chlorine act as a leaving group and removing the negative charge from zinc. The chlorine that left returns to form a bond with zinc, pushing the electrons back on to oxygen and thus forming the ketone.[11]

Variations

Blaise-Maire reaction

The Blaise-Maire reaction is the Blaise ketone synthesis using β-hydroxy acid chlorides to give β-hydroxyketones, which are converted into α,β-unsaturated ketones using sulfuric acid.[12]

Ketone formation from organocadmium compounds

This ketone formation is an identical reaction to the Blaise ketone synthesis. Only instead of organozinc compounds, organocadmium compounds are used and produce higher yields.

See also

References

  1. Bull. Soc. Chim. Fr.
    7: 215–227.
  2. Bull. Soc. Chim. Fr.
    9: 1.
  3. ^ Posner, G. H.; Whitten, C. E. (1976). "Secondary and Tertiary Alkyl Ketones from Carboxylic Acid Chlorides and Lithium Phenylthio(Alkyl)Cuprate Reagents: tert-Butyl Phenyl Ketone". Organic Syntheses. 55: 122; Collected Volumes, vol. 6, p. 248.
  4. ^ Fujisawa, T.; Sato, T. (1988). "Ketones from Carboxylic Acids and Grignard Reagents: Methyl 6-Oxodecanoate". Organic Syntheses. 66: 116; Collected Volumes, vol. 8, p. 441.
  5. PMID 20287882
    .
  6. .
  7. Compt. Rend.
    145: 73-75.
  8. .
  9. .