Octet

Octet / Protecting Groups

Methyl ester

Methyl ester (-) protects carboxylic acids. Install with MeOH, H₂SO₄ (Fischer) or CH₂N₂. Remove with NaOH/H₂O (saponification) or LiOH. Simple protection. Easily hydrolyzed back to acid.

Protecting Group details

Name

Methyl ester

Abbreviation

-

Protects

Carboxylic acids

Install Reagents

MeOH, H₂SO₄ (Fischer) or CH₂N₂

Remove Reagents

NaOH/H₂O (saponification) or LiOH

Notes

Simple protection. Easily hydrolyzed back to acid.

This is one row of the pKa · protecting groups sheet - print all 8 protecting groups on one page.

Protecting Groups

Related Content

Source collection

tert-Butyldimethylsilyl

tert-Butyldimethylsilyl (TBS or TBDMS) protects alcohols. Install with TBSCl, imidazole, DMF. Remove with TBAF (tetrabutylammonium fluoride) or HF. Very common. Stable to many conditions. Removed by fluoride.

Benzyl

Benzyl (Bn) protects alcohols, carboxylic acids. Install with BnBr, NaH (for alcohols). Remove with H₂/Pd (hydrogenolysis). Stable to base and mild acid. Removed under hydrogenation.

Acetyl

Acetyl (Ac) protects alcohols, amines. Install with Ac₂O or AcCl, pyridine. Remove with NaOH/MeOH or K₂CO₃/MeOH. Forms ester (for OH) or amide (for NH₂). Removed by base hydrolysis.

Acetal

Acetal (-) protects aldehydes, ketones. Install with Diol (ethylene glycol), acid catalyst, remove H₂O. Remove with Aqueous acid (H₃O⁺). Stable to base, nucleophiles, reducing agents. Removed by acid.

tert-Butoxycarbonyl

tert-Butoxycarbonyl (Boc) protects amines. Install with Boc₂O, base. Remove with TFA (trifluoroacetic acid) or HCl. Common in peptide synthesis. Orthogonal to Fmoc.

Fluorenylmethyloxycarbonyl

Fluorenylmethyloxycarbonyl (Fmoc) protects amines. Install with Fmoc-Cl, base. Remove with Piperidine (base). Removed by base (not acid). Orthogonal to Boc. Standard in solid-phase peptide synthesis.

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