Protecting Groups¶

Protecting groups are essential tools in peptide synthesis, allowing selective manipulation of functional groups during multi-step synthesis. This section provides a comprehensive reference for the protecting groups used in the Lokey Lab and in peptide chemistry more broadly.

Subsections¶

Amine Protecting Groups —Carbamates (Boc, Fmoc, Cbz, Alloc, and more), sulfonamides (oNBS), amides (TFA), and other amine protection strategies. Includes detailed Boc and Fmoc reference material.
Carboxylic Acid Protecting Groups —Alkyl esters (Me, tBu, Allyl, Bn), silyl esters (TMSE), fluorenyl (Fm), and other carboxylate protection strategies.

Quick Reference¶

Amine Protecting Groups¶

Group	Class	Installation	Removal	Orthogonal To
Boc	Carbamate	Boc2O, Schotten-Baumann	TFA, HCl/dioxane	Fmoc, Alloc, Z
Fmoc	Carbamate	Fmoc-OSu or Fmoc-Cl	Piperidine, DBU	Boc, tBu, Alloc
Cbz (Z)	Carbamate	Cbz-Cl, Schotten-Baumann	Hydrogenolysis, strong acid	Boc, Fmoc
Alloc	Carbamate	Alloc-Cl	Pd(0)/scavenger	Boc, Fmoc, Z
oNBS	Sulfonamide	oNBS-Cl	Thiolate/base	Boc, Fmoc
TFA (trifluoroacetyl)	Amide	TFAA	Mild base, NaBH4	Boc, Fmoc
Trt	Alkyl	Trt-Cl	Dilute acid	Fmoc

Carboxylic Acid Protecting Groups¶

Group	Installation	Removal	Orthogonal To
Me	Esterification	LiOH	Most groups
tBu	tBuOH/DCC or acid conditions	TFA, strong acid	Fmoc
Allyl	Allyl bromide/base	Pd(0)/scavenger	Boc, Fmoc
Bn	Esterification	Hydrogenolysis	Boc, Fmoc
2CT	2-Cl-Trt-Cl	1-2% TFA, HFIP	Fmoc
Fm	Standard esterification	Piperidine, DEA	Boc, tBu