Castro-Stephens coupling

The Castro-Stephens Coupling is a cross coupling reaction between a Copper(I) acetylide and an aryl halide forming a disubstituted alkyne and a copper(I) halide.

Additional recommended knowledge

Daily Visual Balance Check

Essential Laboratory Skills Guide

Recognize and detect the effects of electrostatic charges on your balance

The reaction was discovered in 1963 by chemists Casto and Stephens ^[1] ^[2] and is used as a tool in the organic synthesis of organic compounds. The reaction has similarities with the much older Rosenmund-von Braun synthesis (1916) between aryl halides and copper(I) cyanide and was itself modified in 1973 with as the Sonogashira coupling by adding a palladium catalyst and preparing the organocopper compound in situ.

A typical reaction is the coupling of iodobenzene with the copper acetylide of phenylacetylene in refluxing pyridine to diphenylacetylene:

References

^ The Substitution of Aryl Iodides with Cuprous Acetylides. A Synthesis of Tolanes and Heterocyclics R. D. Stephens and C. E. Castro J. Org. Chem.; 1963; 28(12); pp 3313 - 3315; doi:10.1021/jo01047a008
^ D. C. Owsley and C. E. Castro.Organic Syntheses, Coll. Vol. 6, p.916 (1988); Vol. 52, p.128 (1972) Link.

Category: Carbon-carbon bond forming reactions