(S)-Thalidomide-piperazine-(1S,4r)-cyclohexane-NH-Boc is a conjugate of E3 ligase ligand and linker , consisting of Thalidomide and the corresponding Linker. (S)-Thalidomide-piperazine-(1S,4r)-cyclohexane-NH-Boc can serve as a Cereblon ligand to recruit CRBN protein and serve as a key intermediate for the synthesis of complete PROTAC molecules.