Corey-Fuchs reaction

What is Corey-Fuchs reaction?

The Corey-Fuchs reaction, named after its discoverers in 1972, is a versatile two-step process for synthesizing terminal alkyne compounds. This reaction can be used to create alkyne derivatives by treating the alkynide intermediate with an electrophile before aqueous workup, or to prepare a terminal alkyne through the one-carbon homologation of an aldehyde.

The Corey-Fuchs reaction has also been referred to as the Corey-Fuchs dibromoolefination, Corey-Fuchs homologation, Corey-Fuchs ethynylation, and Corey-Fuchs olefination.

Corey-Fuchs reaction - Corey-Fuchs dibromoolefination - Corey-Fuchs homologation - Corey-Fuchs ethynylation - Corey-Fuchs olefination
Corey-Fuchs reaction

E = Electrophile (see list of acronyms)

The first step of the reaction involves reacting an aldehyde with PPh3 and carbon tetrahalide or haloform to form a dihaloalkene intermediate. The second step entails treating the dihaloalkene with a strong base such as BuLi, LDA, or KOtBu to form a haloalkyne, which undergoes metal-halogen exchange to give lithium alkynide. Aqueous workup of the lithium alkynide intermediate results in the formation of the corresponding terminal alkyne, while treatment with an electrophile prior to workup generates alkyne derivatives.

Corey-Fuchs reaction has broad utility in producing alkyne compounds, particularly those with terminal alkynes.

References

E.J. Corey, P.L. Fuchs, “A synthetic method for formyl → ethynyl conversion (RCHO→RC≡CH or RC≡CR′)” Tetrahedron Letters, 13(36) 3769-3772 (1972)
DOI: 10.1016/S0040-4039(01)94157-7

Shares