Solution-Phase Fmoc-Based Peptide Synthesis for DNA-Encoded Chemical Libraries: Reaction Conditions, Protecting Group Strategies, and Pitfalls

ACS Comb Sci. 2020 Dec 14;22(12):833-843. doi: 10.1021/acscombsci.0c00144. Epub 2020 Oct 19.


Peptide drug discovery has shown a resurgence since 2000, bringing 28 non-insulin therapeutics to the market compared to 56 since its first peptide drug, insulin, in 1923. While the main method of discovery has been biological display-phage, mRNA, and ribosome-the synthetic limitations of biological systems has restricted the depth of exploration of peptide chemical space. In contrast, DNA-encoded chemistry offers the synergy of large numbers and ribosome-independent synthetic flexibility for the fast and deeper exploration of the same space. Hence, as a bridge to building DNA-encoded chemical libraries (DECLs) of peptides, we have developed substrate-tolerant amide coupling reaction conditions for amino acid monomers, performed a coupling screen to illustrate such tolerance, developed protecting group strategies for relevant amino acids and reported the limitations thereof, developed a strategy for the coupling of α,α-disubstituted alkenyl amino acids relevant to all-hydrocarbon stapled peptide drug discovery, developed reaction conditions for the coupling of tripeptides likely to be used in DECL builds, and synthesized a fully deprotected DNA-decamer conjugate to illustrate the potency of the developed methodology for on-DNA peptide synthesis.

Keywords: all-hydrocarbon stapled peptides; aqueous Fmoc-based peptide synthesis; peptide drug discovery.

MeSH terms

  • Chemistry Techniques, Synthetic*
  • DNA / chemistry*
  • Fluorenes / chemistry*
  • Molecular Conformation
  • Peptides / chemical synthesis*
  • Peptides / chemistry
  • Small Molecule Libraries / chemistry*
  • Solutions


  • 9-fluorenylmethoxycarbonyl
  • Fluorenes
  • Peptides
  • Small Molecule Libraries
  • Solutions
  • DNA