(R)-2-(Boc-amino)-4-methyl-4-pentenoic Acid — Chiral Boc-Protected Amino Acid Building Block, ≥98% HPLC, Research Grade Supplier
(R)-2-(Boc-amino)-4-methyl-4-pentenoic acid (CAS 103986-33-0) is a high-purity, (R)-configuration Boc-protected non-proteinogenic amino acid featuring an unsaturated 4-methyl-4-pentenoic acid side chain. Ideal as a chiral building block for peptide synthesis, asymmetric catalysis, and medicinal chemistry applications.
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(R)-2-(Boc-amino)-4-methyl-4-pentenoic acid (CAS 103986-33-0) is a chiral, non-proteinogenic Boc-protected amino acid derivative in which the amine functionality is masked by a tert-butoxycarbonyl (Boc) protecting group and the side chain bears a 4-methyl-4-pentenoic acid moiety with a terminal olefin. The (R)-absolute configuration at the C2 stereocenter imparts specific three-dimensional geometry that is critical for stereoselective transformations in downstream synthesis. This compound belongs to the broader class of Boc-D-allylglycine derivatives, wherein the electronically rich terminal alkene provides a versatile synthetic handle for further elaboration through olefin cross-metathesis, hydroboration-oxidation, epoxidation, dihydroxylation, or thiol-ene radical addition — enabling access to a structurally diverse array of amino acid analogs, peptidomimetics, and chiral intermediates. With a molecular formula of C₁₁H₁₉NO₄ (MW 229.27 g/mol) and ≥98.0% purity by HPLC, this compound meets the stringent quality requirements of academic research laboratories and pharmaceutical development programs alike. The combination of Boc N-terminal protection — which is orthogonal to Fmoc (base-labile) and Cbz (hydrogenolysis-labile) groups — with the unsaturated side chain makes this building block uniquely suited for convergent and fragment-based peptide synthesis strategies that demand chemoselective protecting group manipulation and late-stage side chain functionalization.
As a Research Grade / Pharmaceutical Intermediate Grade product manufactured under ISO 9001:2015 quality management and c-GMP guidelines, UPOR Biotech delivers this chiral building block with comprehensive analytical certification including HPLC purity, enantiomeric excess (chiral HPLC), specific rotation, water content by Karl Fischer titration, residual solvent analysis, and full spectroscopic characterization. The product appears as a white to off-white crystalline powder with a melting point in the range of 68-74°C (classical for Boc-amino acids of this structural class) and a characteristic specific rotation of [α]D²⁰ = +15° to +25° (c=1, MeOH) confirming the (R)-configuration. It is readily soluble in common organic solvents including dichloromethane, DMF, DMSO, ethyl acetate, and methanol — facilitating straightforward incorporation into standard peptide coupling protocols using HBTU, HATU, PyBOP, or DIC/HOBt activation — while limited aqueous solubility and insolubility in hexane provide convenient extractive work-up options during synthesis and purification.
Research Chemical — Chiral Boc-Amino Acid Building Block
(R)-2-(Boc-amino)-4-methyl-4-pentenoic acid is supplied exclusively as a research chemical and pharmaceutical intermediate for laboratory-scale synthesis and process development. The (R)-configured C2 stereocenter, combined with the Boc protecting group and the unsaturated 4-methyl-4-pentenoic acid side chain, provides a trifunctional chiral scaffold enabling orthogonal protecting group strategies, late-stage olefin functionalization, and incorporation of structurally constrained, non-proteinogenic residues into peptide sequences. All shipments include a full Certificate of Analysis (CoA), MSDS, and batch-specific QC documentation. Not intended for human or veterinary therapeutic or diagnostic use.
Technical Specifications
| Product Name | (R)-2-(Boc-amino)-4-methyl-4-pentenoic Acid |
|---|---|
| Synonyms | (R)-2-((tert-Butoxycarbonyl)amino)-4-methyl-4-pentenoic acid; Boc-D-allylglycine derivative; (R)-N-Boc-2-amino-4-methyl-4-pentenoic acid; (R)-2-(Boc-amino)-4-methylpent-4-enoic acid; Boc-(R)-2-amino-4-methyl-4-pentenoic acid; (2R)-2-[(tert-butoxycarbonyl)amino]-4-methylpent-4-enoic acid |
| CAS Number | 103986-33-0 |
| Molecular Formula | C₁₁H₁₉NO₄ |
| Molecular Weight | 229.27 g/mol |
| Appearance | White to off-white crystalline powder |
| Specific Rotation | [α]D²⁰ = +15° to +25° (c=1, MeOH) — (R)-configuration |
| Melting Point | 68-74°C |
| Key Differentiating Feature | (R)-configuration chiral center at C2 with Boc protecting group and unsaturated 4-methyl-4-pentenoic acid side chain bearing a terminal alkene for further derivatization |
| Assay (HPLC) | ≥98.0% |
| Enantiomeric Purity | ≥99.0% ee (chiral HPLC) |
| TLC | Single spot, Rf ~0.4-0.5 (EtOAc/Hexane 1:1, ninhydrin visualization) |
| Related Substances | Total impurities ≤2.0%; any single impurity ≤1.0% |
| Water Content (Karl Fischer) | ≤0.5% |
| Solubility | Soluble in dichloromethane, DMF, DMSO, ethyl acetate, methanol; slightly soluble in water; insoluble in hexane |
| pH (1% aq. suspension) | 3.0-5.0 |
| Loss on Drying | ≤1.0% (105°C, 2 hours) |
| Ash Content | ≤0.1% |
| Heavy Metals | ≤10 ppm (as Pb) |
| Total Plate Count (TPC) | ≤100 CFU/g |
| Yeast & Mold | ≤10 CFU/g |
| E. coli / Salmonella / S. aureus | Absent (per 1 g) |
| Recommended Usage | Peptide synthesis (Boc-SPPS and solution-phase), chiral building block for medicinal chemistry, asymmetric synthesis, bioconjugation, and click chemistry precursor applications |
| Storage Condition | Store at -20°C to +4°C, tightly sealed under inert atmosphere (Ar/N₂), protect from light and moisture |
| Grade | Research Grade / Pharmaceutical Intermediate Grade |
| Certifications | ISO 9001:2015, c-GMP |
| Packaging | Available in 100 mg, 250 mg, 1 g, 5 g, 25 g, and bulk quantities; custom packaging upon request |
| Shelf Life | 24 months from date of manufacture under recommended storage conditions |
Key Benefits
Chiral (R)-Configuration for Stereoselective Synthesis
The defined (R)-absolute configuration at the C2 stereocenter provides predictable three-dimensional geometry essential for stereoselective peptide coupling, asymmetric induction, and the construction of enantiomerically pure pharmacophores. Consistent specific rotation values ([α]D²⁰ = +15° to +25°) and ≥99.0% enantiomeric excess ensure batch-to-batch reproducibility in stereochemically demanding synthetic routes.
Boc-Protected Amine — Orthogonal Protection Strategy Compatible with Fmoc-SPPS
The tert-butoxycarbonyl (Boc) protecting group provides robust N-terminal masking that is stable to bases, nucleophiles, and catalytic hydrogenation but is cleanly removed under mildly acidic conditions (TFA/DCM or HCl/dioxane). This orthogonality with Fmoc (base-labile) and Cbz (hydrogenolysis-labile) protecting groups enables sophisticated multi-step synthetic sequences and fragment condensation strategies without protecting group crossover.
Unsaturated 4-Methyl-4-Pentenoic Acid Side Chain for Further Functionalization
The terminal alkene in the side chain is a powerful synthetic handle enabling olefin cross-metathesis (Grubbs or Hoveyda-Grubbs catalysts), hydroboration-oxidation, Sharpless dihydroxylation, epoxidation, and thiol-ene click chemistry. This allows late-stage diversification of peptide scaffolds, introduction of polar or fluorescent handles, and construction of constrained cyclic peptide architectures — all without disrupting the protected amino acid core.
High Enantiomeric Purity for GMP-Compliant Peptide API Manufacturing
With ≥98.0% HPLC purity and ≥99.0% enantiomeric excess, this building block meets the stringent quality benchmarks required for c-GMP peptide API manufacturing and IND-enabling preclinical studies. Stringent control of related substances (≤2.0% total impurities), residual solvents, water content (≤0.5% KF), and heavy metals (≤10 ppm) ensures that the material is suitable for sensitive biological assays and scalable process chemistry without introducing confounding variables.
Applications
Peptide Synthesis
Incorporation into synthetic peptides as a non-proteinogenic, unsaturated residue using standard Boc-SPPS or solution-phase coupling protocols (HBTU/HATU/DIC-HOBt activation). The Boc group provides orthogonal N-terminal protection for fragment-based assembly and the terminal alkene enables post-synthetic peptide macrocyclization via ring-closing metathesis (RCM).
Chiral Building Block
Serves as a versatile, stereochemically defined intermediate for the total synthesis of complex natural products, alkaloids, and macrocyclic lactams. The (R)-configuration at C2 provides the correct absolute stereochemistry for accessing D-amino acid-containing pharmacophores found in bioactive cyclic depsipeptides and antibiotics.
Medicinal Chemistry / Drug Discovery
Key intermediate for synthesizing peptidomimetic drug candidates, protease inhibitors, integrin antagonists, and constrained peptide scaffolds with improved metabolic stability and oral bioavailability. The unsaturated side chain allows introduction of heterocycles, biotin tags, or fluorophores for SAR and target engagement studies.
Asymmetric Synthesis
Functions as a chiral pool starting material or chiral auxiliary for enantioselective transformations including aldol condensations, Michael additions, and organocatalytic reactions. The Boc-amino group can direct diastereofacial selectivity in additions to the adjacent carboxylic acid derivative.
Bioconjugation
The terminal olefin provides a bioorthogonal handle for site-selective conjugation to biomolecules, surfaces, or polymers via thiol-ene radical addition or olefin metathesis — enabling the construction of peptide-drug conjugates (PDCs), immobilized peptide libraries, and functionalized biomaterials.
Click Chemistry Precursor
The alkene moiety can be converted to azide or alkyne functionalities for copper-catalyzed azide-alkyne cycloaddition (CuAAC) or strain-promoted alkyne-azide cycloaddition (SPAAC), enabling modular assembly of bifunctional probes, fluorescent peptides, and multivalent peptide dendrimers for chemical biology applications.
Frequently Asked Questions
(R)-2-(Boc-amino)-4-methyl-4-pentenoic acid (CAS 103986-33-0) is a chiral, non-proteinogenic Boc-protected amino acid derivative bearing an (R)-configuration at the C2 stereocenter and a 4-methyl-4-pentenoic acid side chain featuring a terminal alkene. In peptide synthesis, it is incorporated as a sterically and electronically distinct residue that introduces unsaturation into the peptide backbone or side chain. The terminal olefin enables further post-synthetic derivatization via olefin metathesis, hydroboration, or thiol-ene click chemistry. The Boc (tert-butoxycarbonyl) group provides orthogonal N-terminal protection, allowing selective deprotection under mildly acidic conditions (TFA) without affecting Fmoc or other base-labile protecting groups in solid-phase peptide synthesis (SPPS) workflows.
The Boc (tert-butoxycarbonyl) group is a widely used amine protecting group in organic and peptide chemistry. It temporarily masks the nucleophilic amino group, preventing undesired side reactions during multi-step synthetic sequences — such as coupling, oxidation, or functional group interconversion at the side chain. The Boc group is stable under basic and nucleophilic conditions but is selectively removed under mildly acidic conditions (e.g., TFA in DCM or 4 M HCl in dioxane), generating the free amine. This orthogonality with Fmoc (base-labile) and Cbz (hydrogenolysis-labile) protecting groups makes Boc-protected amino acids indispensable in convergent and fragment-based peptide synthesis strategies where multiple protecting group manipulations are required.
(R)-2-(Boc-amino)-4-methyl-4-pentenoic acid finds broad utility across multiple domains of synthetic and medicinal chemistry. Key applications include: (1) Peptide Synthesis — incorporation into peptide chains to introduce unsaturation and chirality; (2) Chiral Building Block — use as a stereochemically defined intermediate for constructing complex natural products and analogs; (3) Medicinal Chemistry and Drug Discovery — synthesis of peptidomimetics, protease inhibitors, and constrained peptide scaffolds with improved bioavailability; (4) Asymmetric Synthesis — serving as a chiral auxiliary, ligand precursor, or substrate for enantioselective transformations; (5) Bioconjugation — terminal alkene handles for site-selective conjugation to biomolecules via thiol-ene or metathesis chemistry; and (6) Click Chemistry Precursor — functionalization through copper-catalyzed or strain-promoted cycloaddition for probe and bioconjugate assembly.
Store (R)-2-(Boc-amino)-4-methyl-4-pentenoic acid in a tightly sealed container under an inert atmosphere (argon or nitrogen) at -20°C to +4°C, protected from light and moisture. The product is hygroscopic and should be handled in a dry environment — ideally in a desiccator or glovebox after opening. Allow the container to reach ambient temperature before opening to prevent condensation. Under recommended conditions, the shelf life is 24 months from the date of manufacture. Avoid exposure to strong acids, bases, and oxidizing agents. Use standard personal protective equipment (gloves, lab coat, safety goggles) and work in a well-ventilated fume hood.
UPOR Biotech supplies (R)-2-(Boc-amino)-4-methyl-4-pentenoic acid under ISO 9001:2015 quality management and c-GMP manufacturing standards. Every batch is released with a comprehensive Certificate of Analysis (CoA) documenting assay (HPLC, ≥98.0%), enantiomeric purity (chiral HPLC), specific rotation, appearance, water content (Karl Fischer), residual solvents, and heavy metals analysis. Additional documentation available upon request includes a Certificate of Origin (CoO), Material Safety Data Sheet (MSDS/SDS), GMP manufacturing statement, stability data, elemental analysis, TLC, and full spectroscopic characterization data including 1H NMR, 13C NMR, FT-IR, and HRMS spectra. Custom documentation packages can be tailored to meet specific regulatory or procurement requirements.