Molecular centrality for synthetic design of convergent reactions

With convergent synthesis in mind, we defined a new parameter to quantify the degree of centrality of each atom and bond in a molecule, so-called molecular centrality, which was defined based on squared node distances. The centrality becomes higher as the location of atoms gets closer to the center of a molecule. From the results of validation with 40 organic compounds reported about their total syntheses, it became clear that our molecular centrality was an effective index to evaluate synthetically important bonds. Additionally, it was confirmed that the highest attaching bond centrality of each product moderately correlated with molecular complexity changes of each step. The parameter is quantitative among molecules and suitable for statistical analysis.