ERα degrader 10 is a selective and orally active estrogen receptor α ( ERα ) degrader. ERα degrader 10 exhibits potent ERα binding affinity ( IC 50 of 24.0 nM) and degradation ability ( EC 50 of 5.3 nM). ERα degrader 10 degrades ERα through the proteasome-mediated pathway. ERα degrader 10 can be used for the study of breast cancer.