The central role of chromenols in the biomimetic synthesis of structurally diverse natural product scaffolds

We recently reported scabellone B (1) to be an antimalarial metabolite of the NZ ascidian Aplidium scabellum. One biomimetic route we have explored to the core benzo[c]chromene-1,4-dione structure of 1 is via oxidative dimerisation of chromenol precursors, an example of which is the facile transformation of hemi-tectol 2, to tectol 3, to tecomaquinone 4, natural products isolated from teak wood. Variation in chromenol starting material and reaction conditions yield unusual inter- (5 to 6, 7) and intra-molecular (8 to 9) ring closure products, all of which are representative of biologically active natural products isolated from plants and microbes. The syntheses of 2-9 and the results of biological evaluation will be presented.