Fig. 11
Top row: the DAase IccD catalyzing a decalin core-forming reaction on the bis-diene intermediate that proceeds via the inverse-electron demand Diels–Alder (IEDDA) pathway to generate the 4-hydroxy-2-pyridone type compound ilicicolin H [116]. Bottom row: the formation of the decalin core of the natural product zopfiellamide A [117] from its corresponding bis-diene intermediate is thought to proceed via the normal-electron demand Diels–Alder (NEDDA) pathway catalyzed by a yet-to-be-identified DAase