endo-BCN-PEG8-acid

This endo-BCN-PEG8-acid linker is designed for modular PROTAC synthesis, enabling efficient conjugation to targeting ligands through bioorthogonal chemistry while providing a flexible PEG-based spacer to support productive ternary complex formation. Its handle is suited to iterative linker–ligand assembly workflows, improving synthetic versatility and reproducibility across targeted protein degradation campaigns. The

Structure: The linker contains an endo-bicyclononyne (BCN) bioorthogonal warhead coupled to a poly(ethylene glycol) chain and a terminal carboxylic acid. It features ether linkages within the PEG segment, an aliphatic bicyclic system for strain-promoted reactivity, and a carboxylate-forming functional group for downstream coupling.

Reactivity: BCN-based conjugation proceeds via strain-promoted azide–alkyne cycloaddition with azide-bearing partners under mild, aqueous-compatible conditions, typically without added catalysts. For PROTAC construction, the terminal acid can be activated for amide or ester formation using standard coupling chemistries, enabling attachment to ligands or handles that contain complementary nucleophiles. Reaction performance is commonly optimized by controlling pH, solvent composition, and partner stoichiometry to preserve ligand integrity.