Highly Enantioselective Nickel-Catalyzed Hydrovinylation with Chiral Phosphoramidite Ligands

Abstract

Readily available chiral phosphoramidites are a promising class of ligands for nickel-catalyzed asymmetric hydrovinylation of vinyl arenes. Cooperative effects are operative when ligands with more than one element of chirality are used. Choosing the proper stereochemistry in each part of the modular ligand system leads to high chemoselectivities and excellent enantioselectivities up to 94%. Moreover, the catalysts derived from these ligands proved extremely efficient and remarkably robust performing up to 8300 catalytic turnovers at an initial turnover frequency beyond 1000 h^-1. The large potential for structural variation and their straightforward synthesis make the phosphoramidites currently the best lead structure for catalyst development in this field.