Botryotins A–H, Tetracyclic Diterpenoids Representing Three Carbon Skeletons from a Deep-Sea-Derived <i>Botryotinia fuckeliana</i>

Abstract

Eight unprecedent diterpenoids, botryotins A-H (<b>1</b>-<b>8</b>), were obtained from <i>Botryotinia fuckeliana</i>. They represent three novel carbon skeletons with 6/6/5/5 (<b>1</b>), 6/6/5/6 (<b>2</b>-<b>6</b>), and 6/6/6/5 (<b>7</b> and <b>8</b>) tetracyclic scaffolds. Their structures were determined by detailed spectroscopic analysis and chemical derivatization as well as quantum chemical calculation of the ECD and OR data. Botryotin A (<b>1</b>) exhibited a moderate antiallergic effect (IC₅₀ = 0.2 mM). A plausible biosynthetic pathway for <b>1</b>-<b>8</b> was proposed.