Asymmetric Synthesis of Unnatural α-Amino Acids through Photoredox-Mediated C–O Bond Activation of Aliphatic Alcohols

An efficient protocol for the asymmetric synthesis of unnatural amino acids is realized through photoredox-mediated C–O bond activation of oxalate esters derived from aliphatic alcohols as the radical precursors. The developed system uses chiral glyoxylate-derived N-sulfinyl imine as the radical acceptor and allows quick access to a range of functionalized unnatural amino acids through an atom-economical redox-neutral process with CO2 as the only stoichiometric by-product.