3-{2-[2-(2,2,2-Trifluoroethoxy)ethoxy]ethoxy}-1-propyne

This PROTAC linker supports modular assembly of targeted protein degraders by providing an ether-rich, chemically stable connection motif that can be coupled to compatible ligand scaffolds. Its design emphasizes solubility and conformational flexibility, which are often beneficial for maintaining productive ternary-complex formation. The structure and reactivity considerations that govern linker-to-ligand conjugation are described in detail below.

Structure: The linker is built from multiple ethoxy units terminating in a propargyl alkyne, incorporating an ether network and a trifluoroethoxy substituent. It contains C–O ether linkages and a terminal carbon–carbon triple bond, with predominantly polar, hydrogen-bond-accepting functionality that supports favorable solvation and handling.

Reactivity: The terminal alkyne enables widely used click-type conjugation strategies, including copper-catalyzed azide–alkyne cycloaddition, where the alkyne acts as the dipolarophile. Typical conditions employ copper catalysts with appropriate ligands, often in polar organic solvents or mixed solvent systems, to promote efficient coupling under mild temperatures. The ether and trifluoroethoxy groups are generally compatible with standard PROTAC linker-attachment chemistries, provided base and oxidant sensitivity are considered for the partner functional groups.