Asymmetric bioreductions of beta-nitro acrylates as a route to chiral beta2-amino acids.

[Structure: see text] Reductions of beta-nitroacrylates by Saccharomyces carlsbergensis old yellow enzyme is the key step in a concise route to optically active beta2-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.