Convenient Synthesis of Various Substituted Homotaurines from Alk‐2‐enamides

Abstract Various substituted homotaurines (=3‐aminopropane‐1‐sulfonic acids) 6 were readily synthesized in satisfactory to good yields via the Michael addition of thioacetic acid to alk‐2‐enamides 3 (→ 4 ), followed by LiAlH 4 reduction (→ 5 ) and performic acid oxidation ( Scheme 1 ). The configuration of ‘ anti’ ‐disubstituted homotaurine ‘ anti ’‐ 6h was deduced from the 3‐(acetylthio)alkanamide (= S‐ (3‐amino‐1,2‐dimethyl‐3‐oxopropyl) ethanethioate)‘ anti ’‐ 4h formed in the Michael addition, which was identified via the Karplus equation analysis, and confirmed by X‐ray diffraction analysis. The current route is an efficient method to synthesize diverse substituted homotaurines, including 1‐, 2‐, and N ‐monosubstituted, as well as 1,2‐, 1, N ‐, 2, N ‐, and N , N ‐disubstituted homotaurines ( Table ).