Nicholas reaction

The Nicholas reaction is an organic reaction where a dicobalt octacarbonyl-stabilized propargylic cation is reacted with a nucleophile. Oxidative demetallation gives the desired alkylated alkyne.^[1][2]

Additional recommended knowledge

Daily Sensitivity Test

Correct Test Weight Handling Guide: 12 Practical Tips

Weighing the right way

Several reviews have been published.^[3][4]

Reaction mechanism

The addition of dicobalt octacarbonyl to a propargylic ether (1) gives the dicobalt intermediate 2. Reaction with HBF₄ or Lewis acid gives the key dicobalt octacarbonyl-stabilized propargylic cation (3a and 3b). Addition of a nucleophile followed by a mild oxidation gives the desired substituted alkyne (5).

References

See also

• Pauson-Khand reaction