Estimation of Synthetic Accessibility during Computational Drug Design

Virtual screening makes it possible to design and then test up to millions of structures. On the other hand, not every virtual structure can readily be prepared and tested in reality. Therefore, it is necessary to exclude unsuitable candidates, ideally at the beginning of virtual screening campaign. Three main approaches are used to filter out synthetically unfeasible structures: similarity to starting material, retrosynthetic route and complexity of the structure. These techniques vary in computational demands; they can therefore be used in various stages of screening, and/or combined to improve estimation of synthetic feasibility.