A new ligation method for N-terminal tryptophan-containing peptides using the Pictet–Spengler reaction

Application of a carbon–carbon bond forming reaction for ligating unprotected peptides in acetic acid is described based on a Pictet–Spengler condensation. The peptide segments include a peptide with a Trp at the N-terminal and another with a C-terminal aldehyde, which can be generated through a new cyclic acetal resin.