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]

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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