Post-synthetic modification is a powerful technique allowing access to noncanonical
peptide derivatives in a selective manner, but it has not so far been applied for
the installation of multiple arrays of modified side chains. Here, we use this approach
in solution phase to prepare short N- and C-capped homooligomers of 3-amino-1-methylazetidine-3-carboxylic
acid with all the azetidine side chain functions in free amine form. The key step
is the multiple reductive amination reaction of the corresponding post-synthetically
deprotected secondary amines.
Key words
azetidines - late-stage modification - peptides - reductive amination - protected
amino acid - oligomers