m-PEG2-Tos

m-PEG2-Tos, is a polyethylene glycol-based, tosyl-activated linker designed to support efficient conjugation steps commonly required in targeted protein degradation workflows. Its PEG character can enhance solubility and provide conformational flexibility, while the tosyl functional group enables reliable electrophilic substitution for assembling PROTAC architectures. The following points describe its structure and practical reactivity considerations in detail.

Structure: m-PEG2-Tos is a PEG-containing linker bearing a tosyl (tosylate) leaving group. It features ether linkages along the PEG chain, aromatic sulfonate functionality, and a sulfonate ester linkage that is predisposed to nucleophilic displacement under appropriate conditions. The overall polarity supports aqueous compatibility.

Reactivity: The tosylate functionality is suitable for nucleophilic substitution reactions used to connect PROTAC components. Typical approaches involve reacting the linker with nucleophiles such as amines or oxygen-based nucleophiles under base-mediated conditions to promote displacement of the tosylate. Common solvent systems include polar aprotic media, and reaction temperatures are selected to balance conversion with preservation of sensitive functional groups. Mechanistically, the process proceeds via tosylate leaving-group departure followed by nucleophile capture to form the new C–N or C–O bond.