Acid-Labile Cys-Protecting Groups for the Fmoc/tBu Strategy: Filling the Gap

To address the existing gap in the current set of acid-labile Cys-protecting groups for the Fmoc/fBu strategy, diverse Fmoc-Cys(PG)-OH derivatives were prepared and incorporated into a model tripeptide to study their stability against TFA. S-Dpm proved to be compatible with the commonly used S-Trt group and was applied for the regioselecive construction of disulfide bonds.