Expeditious Preparation of N-Fmoc 2-Aminoethanesulfonyl Chlorides with Functionalized 1-Substituents

Aim and Objective: [(9H-Fluoren-9-yl)methoxy]carbonyl (Fmoc)-protected 2-aminoethanesulfonyl chlorides with various functionalized 1-substituents may be of use as building blocks for the Fmoc strategic synthesis of sulfonopeptides. Material and Method: Fmoc-protected 2-aminoethanesulfonyl chlorides with different functionalized 1- substituents were synthesized via radical addition of N-Fmoc allylamine and xanthates with functionalized Ssubstituents, and subsequent oxidative chlorination with N-chlorosuccimide/HCl. Results: Fmoc-protected 2-aminoethanesulfonyl chlorides with different functionalized 1-substituents were synthesized via radical addition and subsequent oxidative chlorination. The mechanism on the oxidative chlorination is proposed. Conclusion: The current method is an expeditious, convenient, and practical method for the synthesis of Fmocprotected 2-aminoethanesulfonyl chlorides with different functionalized 1-substituents in good to excellent yields.