  A core topic of research in prebiotic chemistry is the search for plausible
synthetic routes that connect the building blocks of modern life such as
sugars, nucleotides, amino acids, and lipids to "molecular food sources" that
have likely been abundant on Early Earth. In a recent contribution, Albert
Eschenmoser emphasised the importance of catalytic and autocatalytic cycles in
establishing such abiotic synthesis pathways. The accumulation of intermediate
products furthermore provides additional catalysts that allow pathways to
change over time. We show here that generative models of chemical spaces based
on graph grammars make it possible to study such phenomena is a systematic
manner. In addition to repro- ducing the key steps of Eschenmoser's hypothesis
paper, we discovered previously unexplored potentially autocatalytic pathways
from HCN to glyoxylate. A cascading of autocatalytic cycles could efficiently
re-route matter, distributed over the combinatorial complex network of HCN
hydrolysation chemistry, towards a potential primordial metabolism. The
generative approach also has it intrinsic limitations: the unsupervised
expansion of the chemical space remains infeasible due to the exponential
growth of possible molecules and reactions between them. Here in particular the
combinatorial complexity of the HCN polymerisation and hydrolysation networks
forms the computational bottleneck. As a consequence, guidance of the
computational exploration by chemical experience is indispensable.
