A Facile Synthesis of α-Amino Esters via Reduction of α-Nitro Esters Using Ammonium Formate as a Catalytic Hydrogen Transfer Agent
作者:Siya Ram、Richard E. Ehrenkaufer
DOI:10.1055/s-1986-31497
日期:——
Various nitroesters 3 were selectively and rapidly reduced to their corresponding amino esters 4 in very good yield using anhydrous ammonium formate as a catalytic hydrogen transfer agent.
The first highly chemo- and enantioselective hydrogenation of beta-nitroacrylates was accomplished with an iridium catalyst (Ir-4) with yields and enantioselectivities of up to 96% and 98% ee, respectively. The resulting alpha chiral beta-nitro propionates are attractive building blocks for the synthesis of chiral beta(2)-amino acids, which are the core scaffolds of bioactive natural products, pharmaceuticals, and beta-peptides.
Pd-catalyzed asymmetric conjugate addition of arylboronic acids to 2-nitroacrylates: a facile route to β2-homophenylglycines
Asymmetric conjugate addition of arylboronic acids to 2-nitroacrylamide in the presence of cationic palladium-Chiraphos complex proceeds with high yield and enantioselectivity (73-89% ee) using as low as 0.05-0.25 mol % of the catalyst. The adducts can be smoothly transformed into the corresponding beta(2)-homophenylglycines in two simple steps. (C) 2013 Elsevier Ltd. All rights reserved.