Are β-Acylaminoacrylates Hydrogenated in the Same Way as α-Acylaminoacrylates? (pages 1184–1188)
Hans-Joachim Drexler, Wolfgang Baumann, Thomas Schmidt, Songlin Zhang, Ailing Sun, Anke Spannenberg, Christine Fischer, Helmut Buschmann and Detlef Heller
Version of Record online: 26 NOV 2004 | DOI: 10.1002/anie.200461716
Five catalyst–substrate complexes of the type [Rh(chiral ligand)(β-dehydroamino acid derivative)]BF4 were characterized for the first time by X-ray analysis (see example). Low-temperature NMR spectroscopy proved that three of these complexes are “major” substrate complexes, which lead to the main product in asymmetric hydrogenation, contrary to the known classical examples with analogous α-dehydroamino acid derivatives.