Description Protein degrader builiding block (S,R,S)-AHPC-C6-PEG3-butyl azide enables the synthesis of molecules fortargeted protein degradation andPROTAC (proteolysis-targeting chimeras) technology. This conjugate contains a von Hippel-Lindau (VHL)-recruiting ligand, a linker with both hydrophobic and hydrophilic moieties, and a pendant azide for click chemistry with a target ligand. Because even slight alterations in ligands and crosslinkers can affect ternary complex formation between the target, E3 ligase, and PROTAC, many analogs are prepared to screen for optimal target degradation.When used with other protein degrader building blockswith a pendant azide group, parallel synthesis can be used to more quickly generate PROTAC libraries that feature variation in crosslinker length, composition, and E3 ligase ligand.