Nucleophilic addition to styrene

Nucleophile addition to styrene derivatives (e.g. 75) coordinated with Cr(CO)3 is another example of addition-electrophile trapping.23,128 Addition of reactive anions is selective at the 3-position of the styrene ligand, leading to the stabilized benzylic anion (76). The intermediate reacts with protons and a variety of carbon electrophiles to give substituted alkylbenzene ligands (in 77) (equation 52). 

Nucleophilic addition to styrene is possible only because the intermediate carbanion is stabilized by conjugation into the benzene ring. It needs a more reactive carbanion than the benzyl anion to initiate the polymerization, and an unstabilized nonconjugated organolithium compound like butyl lithium is the answer. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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