Vyhivskyi Oleksandr, Baudoin Olivier
Department of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland.
J Am Chem Soc. 2024 Apr 15;146(16):11486-92. doi: 10.1021/jacs.4c02224.
We report the first enantioselective total synthesis of diterpenoid randainin D, which possesses a hydroazulenone core with a β-substituted butenolide moiety on the cycloheptane ring. The -5/7 ring system was formed via a highly challenging ring-closing metathesis delivering the tetrasubstituted cycloheptenone. The butenolide moiety was installed via a novel deoxygenative allylation under Ir-photoredox catalysis, employing methyl oxalate as a red/ox tag. Moreover, the developed allylation was successfully utilized in the 7-step total synthesis of (+)-barekoxide. This study suggests that this deoxygenative allylation method is a promising strategy for the formation of Cq-C(sp) bonds (Cq = quaternary center) in the context of natural product synthesis.
我们报道了二萜类化合物兰丹宁 D 的首次对映选择性全合成，它具有一个在环庚烷环上带有 β-取代丁烯内酯部分的氢化薁酮核心。通过极具挑战性的闭环复分解反应形成了 -5/7 环体系，得到了四取代环庚烯酮。丁烯内酯部分是在 Ir-光氧化还原催化下，以草酸甲酯作为氧化还原标签，通过一种新型的脱氧烯丙基化反应引入的。此外，所开发的烯丙基化反应成功应用于 (+)-巴雷考昔的七步全合成中。这项研究表明，这种脱氧烯丙基化方法是在天然产物合成中形成 Cq-C(sp) 键（Cq = 季碳中心）的一种有前景的策略。
