Chromone-Derived Polyketides from the Deep-Sea Fungus Diaporthe phaseolorum FS431

Five new chromone-derived polyketides phaseolorins A-F (1–5), together with nine known compounds, were isolated from the deep-sea derived fungus Diaporthe phaseolorum FS431. The structures of new compounds were determined by analysis of their NMR and high-resolution electrospray ionization mass spectroscopy (HRESIMS) spectroscopic data. The absolute configurations were confirmed by chemical transformations, extensively experimental electron capture detection (ECD) calculations, or X-ray crystallography. Among them, compound 2 represented the first example for a new family of chromone derivative possessing an unprecedented recombined five-member γ-lactone ring. Moreover, the new compounds (1–5) were evaluated for in vitro cytotoxic activities against a panel of human cancer cell lines.