Fig. 1. Derivatization for molecule optimization.

a, Late-stage derivatization enables rapid change of the properties of molecules, but only limited sites of a molecule can be selectively functionalized. Early stage derivatization or de novo modification, on the other hand, could potentially modify any site of the molecule at will, but has to rely on cumbersome de novo multistep synthesis. b, A transition to automated synthesis can eliminate the tedious multistep procedures inherent to manual synthesis; however, despite recent advances, automated multistep synthesis still faces obstacles such as limited synthetic steps and narrow reaction scopes.