Synthesis of α‑Fluoro-α-amino Acid Derivatives via Photoredox-Catalyzed Carbofluorination

A mild, metal-free, regioselective
carbofluorination of dehydroalanine
derivatives has been developed. Alkyl radicals resulting from visible-light
photoredox catalysis engage in a radical conjugate addition to dehydroalanine,
with subsequent fluorination of the newly generated radical to afford
an α-fluoro-α-amino acid. By using a highly oxidizing
organic photocatalyst, this process incorporates nonstabilized primary,
secondary, and tertiary alkyl radicals derived from commercially available
alkyltrifluoroborates to furnish a wide range of fluorinated unnatural
amino acids.