By employing FEM1B for HDAC degradation via FF2049 and comparing it to our previously published HDAC6-selective PROTAC A6, we were able to highlight the impact of the chosen E3 General Procedure A (Amide coupling on resin). This procedure was performed as previously published. This reaction was performed in a scale of 0.21 -3.72 mmol. The preloaded resin 3