The project resulted in development of two important synthetic methodologies relevant for the synthesis of polycyclic terpenes. During its course we found the unexpected new reaction between readily available epoxy enones and potassium O-ethyl xanthate. This discovery allowed the formation of entirely new class of reagents, β-hydroxy α-xanthtyl ketones, which were subsequently used as synthetic equivalents of high energy, difficult to tame sp2 type radicals. The reaction was optimized as a facile, one pot process allowing α-functionalisation of enones in a few simple synthetic steps, allowing access to previously inaccessible molecular architectures. The method was found to be scalable to 2.0 mmol scale. We also discovered that the new reagents, developed previously in Prof. Zard’s research group, α-xanthtyl enones, undergo a clean 1,4-addition with a range of organocuprate reagents. This constitutes a major breakthrough in xanthate chemistry, allowing preparation of a new class of xanthate radical precursors. A library of new building blocks for terpene synthesis were prepared from a few easily accessible, highly versatile starting materials. The utility of radical precursors was demonstrated by their intermolecular additions to unactivated olefins, followed by cyclisation to form bicyclic and tricyclic systems, which are the core structure of many natural products, including polycyclic terpenes. We also progressed the total synthesis of natural product Maritimol, however this project was not completed due to the time constraints that were exacerbated by the Covid pandemic.
