The eight-layer forward reaction network generated by the comprehensive graph-based exploration is shown in Figure . Initialized with the β-D-Glucose (beta isoform of D-Glucose, Node 1-1), two kinetically accessible (reactions with free energy of activation [∆G † ] lower than 45 kcal/mol) products were formed in the first step, namely D-glucose (node 2-1, ∆G † =23.66 kcal/mol. Energy units are kcal/mol unless otherwise stated) and 1,5-Anhydro-D-Fructose (node 2-2, ∆G † =44.17 Figure : A subset of the reaction network of products and intermediates that can be formed after at most eight reactions starting from β-D-Glucose (denoted as grey, node 1-1). Reactions with activation energies less than 45 kcal/mol are shown in the network (all reactions and activation energies can be found in the supplementary information). The number above each arrow refers to the free energy of activation (∆G † ) in kcal/mol. The arrows follow the direction of the network exploration. In some cases, ∆G † is lower for the reverse reaction to that shown. The intermediates highlighted by different colors served as reactants for exploration at the corresponding reaction depth. Species shown in black were considered terminal products by the exploration algorithm (i.e., no further exploration was performed using these species). If multiple arrows point at a species, this indicates that the exploration algorithm found multiple pathways to that species that satisfy the kinetic and thermodynamic thresholds used to make this figure.