Norsampsones A–D, Four New Decarbonyl Polycyclic Polyprenylated Acylphloroglucinols from <i>Hypericum sampsonii</i>

Norsampsones A–D (<b>1</b>–<b>4</b>), four new decarbonyl polycyclic polyprenylated acylphloroglucinols, together with a new biogenetically related compound hypersampsone M (<b>5</b>), were isolated from the aerial parts of <i>Hypericum sampsonii</i>. Norsampsones A–D featured an unprecedented carbon skeleton with the loss of C-2 carbonyl in the phloroglucinol ring. All structures were determined by extensive NMR spectroscopic methods, ECD calculation, and single-crystal X-ray diffraction