The basic assumption in structure-based virtual screening is that compounds with better docking scores have a higher probability for being biologically active . Virtual chemical spaces such as Enamine REALSpace offer billions of structures that are easily synthesizable and thus readily available for drug discovery projects. There are plenty of examples available where docking of virtual chemical spaces has produced biologically active compounds with different kinds of targets (for example, work by Shoichet and colleagues ). These compounds from virtual chemical spaces are readily and rapidly synthesizable (in our drug discovery projects, more than 90 % of virtual compounds picked from Enamine REALSpace have been successfully synthesized and tested in vitro). This is in stark contrast to the virtual compounds originating from generative methods or purely theoretical compound enumerations where the synthesizability of generated compounds is questionable, even though efforts have been made to improve the synthesis accessibility of the compounds .