Semisynthesis, characterization, and biological evaluation of fluorinated analogues of the spirobisnaphthalene, diepoxin-

Diepoxin-eta (1) is a cytotoxic fungal metabolite belonging to the spirobisnaphthalene structural class. In this study, four monofluorinated analogues (2-5) of diepoxin-eta (1) were semisynthesized in a single-step by selectively fluorinating the naphthalene moiety with Selectfluor. The structures of 2-5 were elucidated using a set of spectroscopic and spectrometric techniques and were further confirmed by means of TDDFT-ECD and isotropic shielding tensors calculations. Compounds 2-5 showed equipotent cytotoxic activity to 1 when tested against OVCAR3 (ovarian) and MDA-MB-435 (melanoma) cancer cell lines with IC50 values that range from 5.7 to 8.2 mu M.