The first round of search provided an automatic "literature review" of all reactions relevant to the target synthesis. For convenience, all routes were presented in a linear format without any branches from intermediates. Some examples can be found in Appendix, Fig. . It is interesting to see that top routes ranked by similarity-based scores are similar to the reported route starting from 4PA, while top routes ranked by the popularity metric are similar to the branch of the reported route starting from BPA, see Fig.