Vinyl halides alkynylation

This reaction works with aryl, allylic and 1-alkynyl halides, but not vinylic halides. A vinylic group can be introduced into the 4 position of an isoquinoline by using PdBr2 as the electrophile and an alkene (Scheme 9).10 This process... 

The presumed catalytic cycle for this coupling is the following Once formed from 23, the highly coordinatively unsaturated 14-electron palladium(O) complex 24 participates in an oxidative addition reaction with the aryl or vinyl halide to give the 16-electron palladium(II) complex 25. A copper(I)-catalyzed alkynylation of 25 then furnishes an aryl- or vinylalkynyl palladium(II) complex 27. Finally, a terminating reductive elimination step reveals the coupling prduct 9 and regenerates the active palladium(O) catalyst 24. 

An unprecedented halodephosphorylation of o ,/3-acetylenic and a,/3-ethylenic phos-phonic acid monoesters (27) and (29) with (biscollidine)bromine(I) or (biscollidine) iodine(I) hexafluorophosphate, leading to alkynyl (28) and vinyl halides (30), respectively, has been reported.42... 

Organozinc reagents have been coupled with halides in the synthesis of dienes and other conjugated systems to form new carbon-carbon bonds such reactions have been reviewed477-479. In particular, the reaction of alkynyl zinc reagents with vinyl halides has been used in natural product synthesis, usually catalyzed by palladium complex catalysts. 

Stille reaction the palladium-catalyzed reaction of an aryl or vinyl halide with an organotin reagent, where one of the organic groups is alkynyl, aryl, or vinyl, to give a cross coupled product... 

The original procedure involved the coupling of aryl bromides with secondary amines. However, since then the scope has been expanded to include substrates such as aryl iodides, chlorides, fluorides, triflates, tosylates, nonaflates, iodonium salts, and even boronic acids. While the reaction has not been extensively utilized with vinyl or alkynyl substrates, it can be performed with various heteroaryl halides. Similarly, numerous types of nitrogen-containing coupling partners, including primary amines, imines, various azoles, lactams, and simple amides, can now be used in this reaction. 

Reaction with an amine, AIBN, CO and a tetraalkyltin catalyst also leads to an amide.Benzylic and allylic halides were converted to carboxylic acids electroca-talytically, with CO and a cobalt imine complex. Vinylic halides were similarly converted with CO and nickel cyanide, under phase-transfer conditions.Allylic (9-phosphates were converted to allylic amides with CO and ClTi=NTMS, in the presence of a palladium catalyst. Terminal alkynes were converted to the alkynyl ester using CO, PdBr2, CuBr2 in methanol and sodium bicarbonate. ... 

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