PROTAC ER Degrader-14 (compound 86) is a PTORAC-type Estrogen Receptor/ERR degrader, which is composed of E3 ubiquitin ligase ligand (blue part) (S)-Deoxy-thalidomide , PROTAC Linker (black part) N-Boc-piperazine and target protein ligand (red part) ER ligand-6. Among them, E3 ligase + Linker constitute tert-Butyl (S)-4-(2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)piperazine-1-carboxylate.