mPEG4-propyne

mPEG4-propyne is a polyethylene glycol (PEG)-based propargyl linker designed to support efficient conjugation workflows commonly used in PROTAC assembly. Its PEG segment provides a hydrophilic, sterically accommodating spacer that can improve solubility and facilitate controlled spatial presentation of binding motifs. The terminal propargyl functionality enables bioorthogonal coupling strategies, supporting modular synthesis of targeted protein degraders. The following points describe its structure and practical reactivity considerations in detail below.

Structure: mPEG4-propyne comprises a methoxy-terminated PEG chain bearing a terminal propargyl (alkyne) group. The linker contains repeating ether linkages and a carbon–carbon triple bond at the reactive terminus, yielding a flexible, water-compatible scaffold with typical PEG-like physicochemical behavior.

Reactivity: The terminal alkyne is suitable for copper-catalyzed azide–alkyne cycloaddition or related click-type conjugations used to connect PROTAC components bearing complementary azide handles. Typical protocols employ a Cu(I) source generated in situ, with stabilizing ligands and polar organic/aqueous solvent systems to maintain solubility and reaction efficiency. Reaction design generally follows established click chemistry principles for selective bond formation under mild, experimentally controllable conditions.