Catalytic Asymmetric Hydrogenation of Methyl (E)- and (Z)-2-Acetamido-3-alkylacrylates

Article abstract of DOI:10.1021/jo00338a007

Rhodium-chiral phosphine complex catalyzed homogeneous hydrogenations of methyl (Z)- and (E)-2-acetamido-4-methoxybut-2-enoates ((Z,E)-10), methyl (Z)- and (E)-2-acetamidohex-2-enoates ((Z,E)-16A) and methyl (Z)- and (E)-2-acetamido-4-methylpent-2-enoates ((Z,E)-16B) are reported.With phosphines in which two achiral phosphorus atoms are connected by a chiral four-carbon unit, higher product enantiomeric excesses (ee's) are obtained from E than from Z substrates.With phosphines in which a two-carbon chiral unit separates two achiral phosphorus atoms, Z substrates are preferred.With dipamp (28), both Z and E substrates (particularly (Z,E)-16A) are reduced with high enantioselectivity.The additional oxygen atom in substrates (Z,E)-10 has little effect on product ee with most phosphines.