Fmoc chemistry (revision 4)
Old revision·22:05, 29 Jul 2024·FormularyFrida
| Fmoc chemistry | |
|---|---|
| Temporary group | Fluorenylmethyloxycarbonyl (Fmoc), base-labile |
| Side-chain groups | Acid-labile (tBu, Trt, Pbf) |
| Deprotection reagent | Piperidine in DMF |
| Final cleavage | Trifluoroacetic acid with scavengers |
| Analytical method infobox · conventions | |
Fmoc chemistry is the protecting-group scheme that dominates modern solid-phase peptide synthesis. The temporary N-terminal group, fluorenylmethyloxycarbonyl, is removed by base; the side-chain protecting groups are removed by acid. The two are orthogonal, so each can be removed without disturbing the other.[1]
Its predecessor, Boc chemistry, used acid for both and therefore required a much stronger acid for final cleavage — hydrogen fluoride — with the handling requirements that implies. Boc chemistry was the scheme of the original solid-phase method.[2] Orthogonality is what made peptide synthesis a routine operation.[1]
The cycle
[edit]Fmoc is removed with a solution of piperidine in dimethylformamide, which abstracts the fluorenyl proton and triggers elimination. The released dibenzofulvene is trapped by excess piperidine to prevent it alkylating the peptide.[1]
The resin is then washed and the next Fmoc-protected amino acid coupled using an activating reagent. See Peptide coupling reagent. The cycle repeats once per residue.
References
- ^ a b c Behrendt R, White P, Offer J. "Advances in Fmoc solid-phase peptide synthesis." Journal of Peptide Science 22(1):4–27 (2016). PMID 26785684.
- ^ Merrifield RB. "Solid phase peptide synthesis. I. The synthesis of a tetrapeptide." Journal of the American Chemical Society 85(14):2149–2154 (1963). DOI:10.1021/ja00897a025.