2.2.3. Mutafurans

Mutafurans A–G (**19**–**25**) are brominated ene-ynetetrahydrofurans (Figure 6) that were isolated by Molinski in 2007 from the marine sponge *Xextospongia muta* [27]. Later, Liu reported the isolation of mutafuran H (**26**), a brominated ene-tetrahydrofuran isolated from sponge *Xextospongia testudinaria* within other sterols and brominated compounds [28]. Their structure and absolute configuration were determined by 1D and 2D magnetic resonance, mass spectrometry, and circular dichroism.

**Figure 6.** Structure of mutafurans A–G and the yne-lacking mutafuran H.

Mutafurans A–D showed moderate antifungal activity against the fungus *Cryptococcus neoformans var. grubii,* but were inactive against *Candida albicans* (ATCC14503 and 96–489) and *Candida glabrata* [27]. Furthermore, mutafuran H showed biological activity against *Artemia salina* larvae (LC50 = 2.6 μM) and a significant acetylcholinesterase inhibitory activity (IC50 = 0.64 μM) [28]. No synthetic approach has been reported to date.
