Thalidomide -2,6-diazaspiro[3.4]octane-C-piperidine-C2-O-C-boc is a conjugate of E3 ligase ligand and linker , consisting of Thalidomide and the corresponding Linker. Thalidomide -2,6-diazaspiro[3.4]octane-C-piperidine-C2-O-C-boc can serve as Cereblon ligand to recruit CRBN protein and serve as a key intermediate for the synthesis of complete PROTAC molecules.