Additionally, we sought to synthesise a series of control compounds which should complement the data in CRBN KO and or VHL KO cell lines and allow us to gain a better understanding of the contributions from each ligase. To this end, we synthesised control compounds neg-AB3067 (93), structurally identical to acid chloride (22*, synthesised in Scheme 3), formed after treating (+)-JQ1-acid with thionyl chloride in DCM, to afford the esters of control compounds 93 -95 (Scheme 6).