Isolation, Structure Elucidation, and Total Synthesis of Myrtuspirone A from Myrtus communis

A pair of enantiomeric triketone–phloroglucinol hybrids, (+)- and (−)-myrtuspirone A (1), featuring an unprecedented 3-isopropyl-3H-spiro[benzofuran-2,1′-cyclohexane] backbone, were isolated from the leaves of Myrtus communis. The absolute configuration of each enantiomer of 1 was determined by X-ray diffraction and chemical calculations. Furthermore, the gram-scale total syntheses of (±)-1 and (−)-1 were conducted in four steps using a Michael-N-iodosuccinimide (NIS)-mediated (3 + 2)-annulation reaction. Both (+)- and (−)-1 exhibited antibacterial activities against Gram-positive bacteria including multidrug-resistant strains.