Acetylenic compounds, proton chemical

Electrophilic attack on alkene or alkyne complexes can be a route to cr-organonickel derivatives. One example is the reaction of a cyclohexyne compound with iodomethane shown in Equation (43). The reaction of 77 -phosphino-alkyne complexes with HGl gives a mixture of two isomeric phosphinovinyl compounds with iy//-stereoselectivity (Equation (44)). The regioselectivity of the protonation depends on the electronic properties of the alkyne substituents, and has been correlated with the chemical shift of the G resonances of the two acetylenic carbon atoms. ... 

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