Organocatalytic Asymmetric Transferhydrogenation of β-Nitroacrylates: Accessing β2-Amino Acids
摘要:
We describe a highly efficient and enantioselective Hantzsch ester mediated conjugate reduction of beta-nitroacrylates that is catalyzed by a Jacobsen thiourea catalyst as a key step in a new route to optically active beta2-amino acids.
Epi-quinine-catalyzed asymmetric nitro-Michaeladdition of furanones to β,β,-disubstituted nitroalkenes is described. The reaction proceeded smoothly with 1–5 mol % loadings of epi-quinine catalysts at room temperature, giving the corresponding Michael adducts in high yields (72–93%) with extremely high diastereo- and enantioselectivities (>98/2 dr, syn major; 95–99% ee). This reaction provides an