Bromo-PEG4-alcohol

This Bromo-PEG4-alcohol is a PEG-based linker designed for modular assembly of targeted protein degradation (PROTAC) constructs. Its terminal bromo functionality enables controlled electrophilic coupling to compatible nucleophiles, while the hydrophilic PEG segment supports solubility and favorable linker flexibility. These features can help streamline synthesis of bifunctional degraders, and the following sections describe the structure and practical reactivity considerations in detail.

Structure: The linker comprises a poly(ethylene glycol) chain terminated by an alcohol and a brominated site, providing an ether-rich, flexible scaffold. It contains C–O ether linkages along the PEG backbone and a carbon–bromine bond at the reactive terminus, with an alcohol group suitable for further derivatization.

Reactivity: The bromo terminus is well suited to nucleophilic substitution or related cross-coupling strategies, depending on the partner functional group. For PROTAC assembly, electrophile–nucleophile pairing is typically performed under conditions that preserve the PEG chain and alcohol integrity. Common approaches use polar aprotic solvents and base systems to promote substitution, while cross-coupling may employ transition-metal catalysts and ligand systems matched to the nucleophile type.