Thiazolidine Deprotection Using an Organic Solvent Extractable Aldehyde Scavenger for One-Pot Four-Segment Ligation.

We report a simple and convenient N-terminal thiazolidine (Thz) deprotection strategy and its application in one-pot multisegment ligation. In this strategy, O-benzylhydroxylamine (O-BHA) is used to efficiently and rapidly convert Thz into N-terminal cysteine. O-BHA can be easily separated from the ligation buffer by organic solvent extraction, avoiding the degradation of the peptide thioester by O-BHA. The utility of the O-BHA-based one-pot ligation strategy has been demonstrated in the assembly of CC chemokine ligand-2.