Indole as a Tool in Synthesis. Algorithmic Construction of a Family of Compounds with all Ring Sizes Ranging from 10 to 16

An iterating two-step ring extension process including indolisation–oxidation by ozone applied to an eight membered cyclanone allowed the preparation of seven compounds with ring sizes ranging from 10 to 16. The structure of all derivatives were assigned by spectroscopic data, particularly by 1H and 13C NMR, COSY, HMBC and HMQC experiments.