Annulative Methods Enable a Total Synthesis of the Complex Meroterpene Berkeleyone A
作者:Chi P. Ting、Gong Xu、Xianhuang Zeng、Thomas J. Maimone
DOI:10.1021/jacs.6b10397
日期:2016.11.16
have not been reported despite heavy biosynthetic and medicinal interest. Herein we report the first totalsynthesis of berkeleyone A, a potential gateway compound to a plethora of fungal-derived meroterpenes, in 13 steps. In addition, we have further developed a novel annulation reaction for the synthesis of hydroxylated 1,3-cyclohexadiones in a single step.
尽管生物合成和药用价值很高,但尚未报道衍生自 3,5-二甲基橙霉酸 (DMOA) 和法呢基焦磷酸的复合萜烯的合成途径。在本文中,我们报告了伯克利酮 A 的首次全合成,这是一种潜在的通往大量真菌衍生的萜类化合物的门户化合物,分 13 个步骤。此外,我们进一步开发了一种新的环化反应,用于一步合成羟基化 1,3-环己二酮。
Total Synthesis of (±)-Berkeleyone A
作者:Masha Elkin、Suzanne M. Szewczyk、Anthony C. Scruse、Timothy R. Newhouse
DOI:10.1021/jacs.6b12914
日期:2017.2.8
A 13-step total synthesis of the fungal meroterpenoid berkeleyone A is reported. The molecular skeleton is formed using the first examples of two critical construction reactions: (1) an epoxide-initiated, β-ketoester-terminated polycyclization, and (2) an isomerization-cyclization cascade to generate the remaining bicyclo[3.3.1]nonaneframework. The resulting 6-step synthesis of the carbocyclic core
报道了真菌类萜 berkeleyone A 的 13 步全合成。分子骨架是使用两个关键构建反应的第一个例子形成的:(1)环氧化物引发的、β-酮酯封端的多环化反应,以及(2)异构化-环化级联反应以生成剩余的双环 [3.3.1] 壬烷框架。由此产生的 berkeleyone 天然产物碳环核心的 6 步合成已被用于获取 protoaustinoid A 和 berkeleyone A,并将有助于未来对相关天然产物来源的生物合成研究。
Spiro-Ring Formation is Catalyzed by a Multifunctional Dioxygenase in Austinol Biosynthesis
Austinol, a fungal meroterpenoid derived from 3,5-dimethylorsellinic acid, has a unique chemical structure with a remarkable spiro-lactone ring system. Despite the recent identification of its biosynthetic gene cluster and targeted gene-deletion experiments, the process for the conversion of protoaustinoid A (2), the first tetracyclic biosynthetic intermediate, to the spirolactone preaustinoid A3 (7) has remained enigmatic. Here we report the mechanistic details of the enzyme-catalyzed, stereospecific spiro-lactone ring-forming reaction, which is catalyzed by a non-heme iron-dependent dioxygenase, AusE, along with two flavin monooxygenases, the 5'-hydroxylase AusB and the Baeyer-Villiger monooxygenase AusC. Remarkably, AusE is a multifunctional dioxygenase that is responsible for the iterative oxidation steps, including the oxidative spiro-ring-forming reaction, to produce the austinol scaffold.