Thalidomide-propargyl is the Thalidomide-based Cereblon ligand used in the recruitment of CRBN protein. Thalidomide-propargyl can be connected to the ligand for protein by a linker to form the IMiD containing PROTACs[1].
[1]. Wurz RP, et al. A "Click Chemistry Platform" for the Rapid Synthesis of Bispecific Molecules for Inducing Protein Degradation. J Med Chem. 2018 Jan 25;61(2):453-461.