Thiazolidine\nDeprotection Using an Organic Solvent\nExtractable Aldehyde Scavenger for One-Pot Four-Segment Ligation

We report a simple and convenient N-terminal thiazolidine\n(Thz)\ndeprotection strategy and its application in one-pot multisegment\nligation. In this strategy, <i>O</i>-benzylhydroxylamine\n(O-BHA) is used to efficiently and rapidly convert Thz into N-terminal\ncysteine. O-BHA can be easily separated from the ligation buffer by\norganic solvent extraction, avoiding the degradation of the peptide\nthioester by O-BHA. The utility of the O-BHA-based one-pot ligation\nstrategy has been demonstrated in the assembly of CC chemokine ligand-2.