Alkyne derivatives copper-catalyzed halides, terminal

An elegant method for linking terminal alkynes with aromatic compounds and olefins is the Sonogashira reaction [15]. The palladium-catalyzed reaction enables the simultaneous introduction of two or even more alkyne units and thereby makes it possible to synthesize acetylene derivatives, for example hexaalkynyl-benzenes [16], (eq. (7)), which can be obtained only with difficulty by other methods. It has been shown by Herrmann, Beller, and co-workers that the copper reagent is not necessary as a co-catalyst for the coupling of terminal alkynes with sp -carbon halides. By using phosphapalladacyclic catalysts 1 the... 

Under certain conditions, alkynes can be coupled to aryl halides.280 When aryl halides react with copper acetylides to give 1-aryl alkynes such as 431, the reaction is known as Stephens-Castro coupling.28l Both aliphatic and aromatic substituents can be attached to the alkyne unit, and a variety of aryl iodides has been used. A palladium-catalyzed variation is also known in which an aryl halide reacts with a terminal alkyne to give derivatives such as 434. In this variation, called the Sonogashira coupling,2 2 jhe reaction is catalyzed by... 

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