Alkynes reaction with organocopper reagents

Alkenes. Normant et al. have developed a method for a regiospecific synthesis of 1-alkenes by addition of organocopper reagents to 1-alkynes. The copper reagents are prepared by the reaction of a Grignard reagent with cuprous bromide in ether at -40. The 1-alkyne is then added to this solution to form a... 

Scheme 10.112 The carbometallation reaction of fluoroalkylated alkynes with organocopper species derived from the Grignard reagents [92].

Alkenes with perfluoroalkyl substituents have been prepared by the reaction of perfluoroalkyl iodides with terminal alkynes in the presence of ultrasonically dispersed zinc and Cul. A general procedure for the formation of organocopper reagents from alkyl and aryl halides and lithium metal in the presence of Cul or l-pentynylcopper(I) under ultrasonic irradiation has also been described. ... 

Transmetalation from Zr to Cu is a highly beneficial process as it combines the ease of preparation of organozirconocenes from alkenes and alkynes with the wide scope of organocopper reagents in organic synthesis. Schwartz and coworkers were first to demonstrate transmetalation to Cu in their report on the reductive dimerization of alkenylzirconocenes [94]. Virgili et al. used this transformation to prepare dialkoxy-1,3-butadienes [95]. The copper-mediated coupling of alkenylzirconocene 85 and phenethynyl bromide was reported to yield 86 [96] (Scheme 19). The latter two reactions can also be mediated by ox-ovanadium complexes [97]. 

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