PEG3-C4-OBn

PEG3-C4-OBn, is designed to provide a flexible, hydrophilic spacer that can connect two binding motifs while supporting efficient ternary complex formation. Its ethylene glycol–based segment and protected alcohol functionality help tune solubility and spatial presentation of warhead and recruiter groups. The subsequent sections describe its structural features and practical considerations for linker incorporation into targeted protein degradation constructs.

Structure: The linker contains an oligomeric polyethylene glycol segment coupled to a C4 alkyl spacer and a benzyl-protected ether alcohol terminus. It comprises ether linkages and saturated carbon frameworks, offering conformational flexibility and enhanced polarity. The benzyl ether provides a stable handle for later deprotection and functionalization.

Reactivity: For PROTAC assembly, the benzyl-protected oxygen functionality is typically carried through coupling steps using conditions compatible with benzyl ethers, then removed under standard hydrogenolysis or oxidative deprotection strategies to reveal a reactive alcohol. Subsequent formation of amide or carbamate linkages can be achieved via activated carboxylic acid derivatives. Solvent systems are selected to maintain PEG solubility and minimize side reactions.