Fig. 6. Examples of pairs of compounds from the test set that are similar to each other (Tanimoto > 0.8), where a retrosynthetic route could be found for one example in the pair but not the other. In each case only a slight modification of the compound leads to a change in the outcome from the CASP tool, consider (a) addition of two ortho-methyl groups on the terminal phenyl ring, (b) substitution of a cyclohexane moiety for a cyclopropane, and (c) a change in substitution pattern and ring morphology, leads to a change in outcome from solved to unsolved.
