straightforward and general synthesis of nitroolefins fromnitricoxide (NO) and olefins is presented. The direct nitration of aromatic olefins, allyl compounds, and acrylic acid derivatives proceeds smoothly at room temperature with high regioselectivity and good yields. The advantages of this novel procedure compared to established nitration procedures are demonstrated.
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.
Organocatalytic Asymmetric Transferhydrogenation of β-Nitroacrylates: Accessing β<sup>2</sup>-Amino Acids
作者:Nolwenn J. A. Martin、Xu Cheng、Benjamin List
DOI:10.1021/ja8069852
日期:2008.10.22
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.
Asymmetric Bioreductions of β-Nitro Acrylates as a Route to Chiral β<sup>2</sup>-Amino Acids
作者:Magdalena A. Swiderska、Jon D. Stewart
DOI:10.1021/ol062612f
日期:2006.12.1
Reductions of beta-nitroacrylates by Saccharomyces carlsbergensis old yellow enzyme is the key step in a concise route to optically active beta(2)-amino acids. The enzymatic reductions occur with 87 - 96% ee, with larger substrates providing greater stereoselectivities. This work extends enantioselective enzymatic alkene reductions to include acyclic systems with weakly coordinating substituents.