Castro-Stephens coupling

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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.

Castro-Stephens reaction

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:

Application of Catsro-Stephens coupling with phenyliodine

References

  1. 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
  2. D. C. Owsley and C. E. Castro.Organic Syntheses, Coll. Vol. 6, p.916 (1988); Vol. 52, p.128 (1972) Link.