Novel anti-β-Functionalized γ,δ-Unsaturated Amino Acids via a Thio-Claisen Rearrangement. -A significantly improved approach to novel title compounds is developed. The mild conditions allow the introduction of base-labile functional groups. -(LIU, Z.; QU, H.; GU, X.; LEE, K.-S.; GROSSMAN, B.; KUMIROV, V. K.; HRUBY*, V.