The origins of the enantioselection in asymmetric catalytic hydrogenation of amino-acid precursors

Abstract

Comparison of c.d. spectra confirms that the isolated diastereomer of the initial catalyst-substrate adduct in the [Rhchiraphos]⁺-catalysed [chiraphos =(2S, 3S)-2,3-bis(diphenylphosphino)butane] hydrogenation of ethyl (Z)-α-acetamidocinnamate is also the major diastereomer in solution; this supports the conclusion that the prevailing chirality of the product has its origins in the minor diastereomer.