Peroxide Natural Products from <i>Plakortis zyggompha</i> and the Sponge Association <i>Plakortis halichondrioides</i>–<i>Xestospongia deweerdtae</i>: Antifungal Activity against <i>Cryptococcus gattii</i> Matthew T. Jamison Doralyn S. Dalisay Tadeusz F. Molinski 10.1021/acs.jnatprod.5b00951.s001 https://acs.figshare.com/articles/journal_contribution/Peroxide_Natural_Products_from_i_Plakortis_zyggompha_i_and_the_Sponge_Association_i_Plakortis_halichondrioides_i_i_Xestospongia_deweerdtae_i_Antifungal_Activity_against_i_Cryptococcus_gattii_i_/2076748 <i>Cryptococcus gattii</i> is a human pathogen and causative agent of a pernicious, sometimes fatal, disseminated fungal disease. Investigation of antifungal extracts of the marine sponge association <i>Plakortis halichondrioides</i>–<i>Xestospongia deweerdtae</i> and the sponge <i>Plakortis zyggompha</i> from the Bahamas led to the discovery and isolation of 6-<i>epi</i>-7,8-dihydroplakortide K (<b>1</b>), plakortide AA (<b>2</b>), and three new plakinic acids, N–P (<b>4</b>–<b>6</b>; unstable 1,2-dioxolanes bearing benzyl-substituted conjugated dienes), along with known plakinic acids L, K, and M. Chiroptical comparisons and DFT calculations of <sup>13</sup>C NMR chemical shifts were used to assign the absolute stereostructure of <b>4</b>. The stereospecific base-promoted rearrangement–saponification of <b>1</b> to <b>10</b> was briefly investigated and showed tight kinetic control and stereospecific formation of the new C-2 stereocenter with inversion at C-3. Plakinic acid M and plakortides <b>9</b> and <b>11</b> exhibited antifungal activity against <i>C. gattii</i> (MIC<sub>90</sub> = 2.4 to 36 μM), but plakinic acids N–P were inactive under the same conditions. 2016-02-09 17:06:07 13 C NMR chemical shifts Plakortis zyggompha Chiroptical comparisons MIC 90 Antifungal Activity antifungal activity Cryptococcus gattii Cryptococcus gattii DFT calculations antifungal extracts deweerdtae plakinic acids L sponge Plakortis zyggompha stereospecific formation plakinic acids Peroxide Natural Products halichondrioide plakortides 9