4.1.2. Myrothecols

In 2020, (−)-1*S*-myrothecol (**(***−***)-112**), (+)-1*R*-myrothecol (**(+)-112**), and methoxymyrothecol (**113**) (Figure 28) were isolated from deep-sea fungus *Myrothecium sp.* BZO-L062 [100]. Enantiomers **(***−***)-112** and **(+)-112** were separated by normal-phase chiral

HPLC, and their absolute configurations were established by ECD spectra. Compounds **(***−***)-112** and **(+)-112** display anti-inflammatory activity, inhibit nitric oxide formation in lipopolysaccharide-treated cells (RAW264.7), and present antioxidant activity in the 2,2- azino-*bis*(3-ethylbenzothiazoline-6-sulfonic acid) and oxygen-radical absorbance capacity assays.

**Figure 28.** Structure of (−)-1*S*-myrothecol (**(***−***)-112**), (+)-1*R*-myrothecol (**(+)-112**), and methoxymyrothecol (**113**).

4.1.3. Astronypyrone, Astronyquinone, and Astronyurea

In 2016, astronypyrone (**114**), astronyquinone (**115**), and astronyurea (**116**) (Figure 29) were isolated from the marine fungus *Astrosphaeriella nypae* BCC 5335 [101]. Compound **115** shows weak antituberculosis activity (with a MIC value of 50 μg/mL) and presents cytotoxicity against African green monkey kidney fibroblast cell lines (IC50 = 17.4 μg/mL).

**Figure 29.** Structure of astronypyrone (**114**), astronyquinone (**115**), and astronyurea (**116**).

4.1.4. Sinularones

Sinularones A-I were isolated in 2012 from the marine soft coral *Sinularia* sp. [102]. Their structures were elucidated by IR, MS, CD, 1D, and 2D NMR. Among them, sinularones E (**117**) and F (**118**) contain a tetrahydrofuran moiety (Figure 30).

**Figure 30.** Structure of sinularones E (**117**) and F (**118**).

Their first total synthesis, based on a hydrogenative metathesis of enynes, was reported in 2020 by Fürstner and coworkers [103]. The required 2,5-*cis*-tetrahydrofuran derivative **119** was readily obtained by hydrogenation (over Rh/Al2O3) of commercial furane **120**. Three further steps were needed to obtain silyl ether **121**, which in the presence of ruthenium catalyst **122** and H2 undergoes a hydrogenative metathesis. Later deprotection with TBAF produces **117** with 65% yield over both steps. Sinularone F (**118**) synthesis utilizes the same strategy (Scheme 13).

**Scheme 13.** Synthesis of sinularone E (**117**). A similar strategy was applied to sinularone F (**118**).
