Chiral metal complexes hydrovinylation

This Mulheim chemistry has been highlighted by the discovery of the highly enantioselective hydrovinylation of styrene to produce chiral 2-phenyl-1-butene in 95.2% ee for a 10 kg-scale reaction (Scheme 60) (132). The Ni catalyst is very reactive and contains the unique chiral dimeric aminophosphine ligand derived from (R)-myrtenal and (S)-1-phenylethylamine. Computer simulations suggest that in this chiral Ni complex, the phenyl substituent of the chiral phenylethyl group acts as a windshield wiper across the catalytically active metal center. This... 

Besides the metal complexes based on Ni and Pd that were previously proved suitable for the asymmetric hydrovinylation reactions, Ru and Co complexes have also been employed in this type of transformation. The one sole example of Ru-catalyzed enantioselective hydrovinylation was reported by the List group in 2012. In their initial studies, they envisioned that Ni complexes with chiral counteranions might enable the desired reaction. However, it was found that these species either were unreactive or did not furnish enantioselective control in the hydrovinylation reactions. In this context, Jiang and List focused their attention on Ru catalysis (Table 9.6). Systematic evaluation on the effects of Ru complexes ligated by different phosphine ligands as well as various chiral phosphate anions introduced by the corresponding silver salts demonstrated that the combination of Ru complex Ru-3 and additive Ag-1 was the optimal catalyst, leading to acceptable results (entry 8). 

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