(R)-1-[3,5-Bis(trifluoromethyl)phenyl]-3-[1-(dimethylamino)-3-methylbutan-2-yl]thiourea, with CAS number 1048692-61-0, is a chemical compound featuring a thiourea core substituted with a 3,5-bis(trifluoromethyl)phenyl group and a dimethylamino-substituted branched alkyl chain. The (R)-configuration at the chiral center is a critical structural feature for its biological activity. This compound is a key component in the field of targeted protein degradation. It functions as a high-affinity ligand for the E3 ubiquitin ligase Cereblon (CRBN). Specifically, it is known as a "CRBN ligand" or "Cereblon binder." Its primary application is as a building block for the design and synthesis of Proteolysis-Targeting Chimeras (PROTACs) and other bifunctional degraders. By conjugating this ligand to a warhead that binds a protein of interest (POI) via a suitable linker, researchers can create molecules that recruit the POI to the CRBN E3 ligase complex, leading to its ubiquitination and subsequent proteasomal degradation. The presence of the 3,5-bis(trifluoromethyl)phenyl group is a hallmark of potent CRBN binders, contributing to strong binding affinity. As such, this compound is not a general-purpose synthesis intermediate but a specialized tool molecule central to modern drug discovery efforts focused on degrading disease-causing proteins.