Fig. 4

Impossible parent scaffolds in Scaffold Generator. A Dodecahydro-s-indacene (PubChem CID 13214318) representing an example scaffold cannot be dissected in a way that turns former ring atoms into linker atoms in the created parent scaffold. B Tricyclo[7.2.1.01,6]dodecane (PubChem CID 12,758,808) representing an example scaffold cannot be dissected in a way that creates a parent scaffold with a spiro-ring system which was not there in the molecule before