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Formamidine Linker for the Reversible Crosslinking of Two Alkyl Amines in Peptide Stapling

Precise Construction of an Antimicrobial Peptide Targeting Bacterial Cell Membranes Derived From Natural Peptides.

Overcoming Proteolytic Instability in a β-Turn Antimicrobial Peptide via Cyclization and Stereochemical Inversion to Combat MDR Bacteria

Fluorescent Macrocyclization: Metal-Free Coupling Based on Glycine and Salicylaldehyde Enables One-Step Peptide Labeling and Cyclization

Interaction of Polypeptides with Hair Under Different Reducing Environments

Water-Based Amino Acid Coupling Technology for Sustainable Solid-Phase Peptide Synthesis

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Light-Driven Boron-Carbon Bond Construction: Synthesis of Carboranyl Peptides Targeting BNCT

Teriparatide: An Anabolic Agent for the Treatment of Osteoporosis

Advances and Challenges in Peptide Vaccines

0102030405

Fmoc Solid-Phase Peptide Synthesis and Common Fmoc-Protected Amino Acids

2025-08-12

Introduction to Fmoc Solid-Phase Synthesis

Fmoc solid-phase synthesis was pioneered by Eric Atherton and Bob Sheppard at the University of Cambridge in the late 1970s (systematically refined by Chan and White). Its core methodology employs the Fmoc (9-fluorenylmethoxycarbonyl) group as the α-amino protecting group for amino acids. Peptide chains are stepwise assembled on an insoluble resin through gentle piperidine deprotection (avoiding acid-induced damage to the peptide chain) and activated carboxyl-group coupling. Key advantages include:

1.Mildness and Safety:

The Fmoc group exhibits strong resistance to acids (e.g., TFA), while side-chain protecting groups (such as Boc) require acid-mediated cleavage

Only a single TFA cleavage step is required to simultaneously release the peptide from the resin and remove side-chain protections, eliminating the side-reaction risks associated with repeated strong-acid treatments in Boc chemistry.

2.Efficiency and Control:

Byproducts are rapidly removed via stepwise washing;

The characteristic UV absorption of the Fmoc group enables real-time reaction monitoring.

3. Versatile Application Compatibility:

Compatible with acid-sensitive amino acids (e.g., tryptophan/methionine) and complex modified peptides.

Serves as the foundational technology for automated peptide synthesizers (e.g., Dilunbio 386 Pro) and industrial peptide drug production, progressively replacing traditional Boc synthesis.

The following table compiles common Fmoc-amino acids used in solid-phase peptide synthesis.

Common Fmoc-Protected Amino Acids for Solid-Phase Peptide Synthesis
Code	Name	MW	Structural Formula	Molecular Formula	CAS	Properties
A	Fmoc-Ala-OH	311.33		C₁₈H₁₇NO₄	35661-39-3	Aliphatic hydrophobic amino acid with neutral charge
R	Fmoc-Arg(Pbf)-OH	648.77		C₃₄H₄₀N₄O₇S	154445-77-9	Basic polar amino acid with Pbf-protected guanidyl group blocking side reactions
N	Fmoc-Asn(Trt)-OH	596.67		C₃₈H₃₂N₂O₅	132388-59-1	Polar charge-neutral amino acid containing Trt-protected amide moiety resisting hydrolysis
D	Fmoc-Asp(OtBu)-OH	411.45		C₂₃H₂₅NO₆	71989-14-5	Acidic polar amino acid with OtBu-protected β-carboxyl group suppressing unintended conjugation
C	Fmoc-Cys(Trt)-OH	585.71		C₃₇H₃₁NO₄S	103213-32-7	Sulfur-containing polar neutral amino acid with Trt-protected thiol group preventing oxidation
Q	Fmoc-Gln(Trt)-OH	610.70		C₃₉H₃₄N₂O₅	132327-80-1	Polar charge-neutral amino acid containing Trt-protected carboxamide group
E	Fmoc-Glu(OtBu)-OH	425.47		C₂₄H₂₇NO₆	71989-18-9	Acidic polar amino acid with OtBu-protected γ-carboxyl group
G	Fmoc-Gly-OH	297.31		C₁₇H₁₅NO₄	29022-11-5	Simplest aliphatic hydrophobic amino acid with neutral charge and non-chiral structure
H	Fmoc-His(Trt)-OH	619.71		C₄₀H₃₃N₃O₄	109425-51-6	Basic polar amino acid containing Trt-protected imidazolyl group
I	Fmoc-Ile-OH	353.41		C₂₁H₂₃NO₄	71989-23-6	Branched-chain aliphatic hydrophobic amino acid with neutral charge
L	Fmoc-Leu-OH	353.42		C₂₁H₂₃NO₄	35661-60-0	Branched-chain aliphatic hydrophobic amino acid with neutral charge
K	Fmoc-Lys(Boc)-OH	468.54		C₂₆H₃₂N₂O₆	71989-26-9	Basic polar amino acid with Boc-protected ε-amino group
M	Fmoc-Met-OH	371.45		C₂₀H₂₁NO₄S	71989-28-1	Thioether-containing hydrophobic amino acid, neutral charge with oxidizable methylthio moiety
F	Fmoc-Phe-OH	387.43		C₂₄H₂₁NO₄	35661-40-6	Aromatic hydrophobic amino acid with neutral charge containing phenyl ring
P	Fmoc-Pro-OH	337.37		C₂₀H₁₉NO₄	71989-31-6	Heterocyclic secondary amino acid with unique constrained-ring structure and hydrophobic character
S	Fmoc-Ser(tBu)-OH	383.44		C₂₂H₂₅NO₅	71989-33-8	Hydroxyl-containing polar residue, neutral charge/tBu-ether protected suppressing ether cleavage
T	Fmoc-Thr(tBu)-OH	397.46		C₂₃H₂₇NO₅	71989-35-0	Polar hydroxylic amino acid, neutral charge/tBu-protected
W	Fmoc-Trp(Boc)-OH	526.58		C₃₁H₃₀N₂O₆	143824-78-6	Indole-containing aromatic residue, polar neutral/Boc-protected pyrrole nitrogen
Y	Fmoc-Tyr(tBu)-OH	459.53		C₂₈H₂₉NO₅	71989-38-3	Phenolic hydroxyl-containing aromatic amino acid, polar neutral/tBu-ester protected preventing O-acylation
V	Fmoc-Val-OH	339.39		C₂₀H₂₁NO₄	68858-20-8	Branched-chain aliphatic hydrophobic amino acid with neutral charge

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