All-carbon quaternary centers via catalytic asymmetric hydrovinylation. New approaches to the exocyclic side chain stereochemistry problem.

1-Alkylstyrenes undergo efficient hydrovinylation (coupling with ethylene) in the presence of 1 mol % of a Ni catalyst prepared from [(allyl)NiBr]2, Na+BAr4- (Ar = 3,5-bistrifluoromethylphenyl), and phosphoramidite ligands (derived from enantiopure binaphthols and 1-methylbenzylamines), giving hydrovinylation products in excellent yields and enantioselectivities. The products contain a quaternary center with two versatile latent functionalities, an arene and a vinyl group, useful for further synthetic elaborations.