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.
A highlyenantioselectiveFriedel–Craftsalkylation reaction of indoles with acyclic α-substituted β-nitroacrylates is developed under the catalysis of Ni(ClO4)2–bisoxazoline complex at 1 mol % catalyst loading, affording chiral indolic β-nitroesters bearing all-carbon quaternary stereocenters in excellent yields and ees of up to 97%. Transformation of one of the products to β2,2-amino ester and t