New insight into the mechanism of catalytic hydrogenation allows the structure of the key intermediate in asymmetric hydrogenation to be predicted

Article abstract of DOI:10.1016/S0040-4020(98)00992-2

An approach has been developed to determine the regioselectivity of hydrometalation in homogeneous and heterogeneous hydrogenation of alkenes. By studying the electronic effects on the orientation of hydrometalation it is found with palladium and rhodium that this key step is a two electron process that can occur by two modes (a Pd(δ*+-) H(δ-) or b Pd(δ-)- H(δ+)). This provides valuable information about the structure of the metal-alkyl intermediate and helps rationalise how chiral induction occurs.