From β-enaminoesters to optically active β-amino acids and functional dihydropyridine derivatives

摘要

Optically active β-amino acid derivatives are intermediates of great interest in pharmaceutical industry for the access to a variety of biologically active products. We have investigated their preparation via enantioselective hydrogenation of prochiral enamides in the presence of rhodium catalysts and have demonstrated that the asymmetric hydrogenation of (Z)- and (E)-β-acetamidoacrylates can be carried out in the presence of rhodium-diphosphine precatalysts under low hydrogen pressure with Et-Duphos and Et-BPE as optically active ligands. The use of two equivalents of optically active monophosphite also provides an efficient catalytic system for the enantioselective hydrogenation of the (E)-isomers.