Bioinspired\nSemisynthesis and Structure Revisions\nof Chlorinated Norsesquiterpenoids Rumphellatins A–C

The first synthesis of chlorine-containing hemiketals,\nrumphellatins\nA–C (<b>1</b>–<b>3</b>), previously inaccessible\nby means of total synthesis, was achieved starting from commercially\navailable (−)-β-caryophyllene oxide (<b>7</b>).\nStructures of rumphellatins A (<b>1</b>) and C (<b>3</b>) were revised, while structures of rumphellatin B (<b>2</b>) and intermediate rumphellolide C (<b>19</b>) were confirmed.\nThe study expands availability of exotic norsesquiterpenoids for profiling\ntheir biological activity as well as facilitates the elucidation of\nbiosynthetic pathways of their formation.