Cascade Cyclization Synthesis of Fused Polycyclic Ethers

在这个由化学系化学合成计划资助的项目中，埃默里大学的Frank E.McDonald教授正在开发结构复杂的海洋天然产物的高效制备，例如Brevenal，一种无毒的空气传播毒素抑制剂，由热带和亚热带海洋地区(包括墨西哥湾)的赤潮事件自然产生。为了减少构建这种结构复杂的化合物所需的大量步骤，该研究计划通过开发一种新的顺序环化策略来应对这一挑战，该策略用于多环醚的化学合成，主要目标结构为缩醛。这项研究的更广泛的影响包括一个合作练习，在这个练习中，学生，包括那些参与这个项目的人，提高他们的科学沟通技能，以更好地向公众解释科学家做什么，以及为什么他们的工作很重要。学生们就正在进行的或最近完成的研究经验进行简短的演讲，面向不同的受众，包括受过教育的成年非科学家和小学生，并接受同行学生的陈述反馈。为了有效地制备多环醚天然产品，埃默里小组正在努力利用立体和区域选择性的成环反应级联反应。这项工作将稠合多环醚合成中级联环合反应的研究范式从狭隘地关注困难的内模聚环氧化物环化反应，转移到本项目中包括外模氧环化反应在内的其他级联环化反应方法上。拟议的工作包括提高科学交流技能的练习，这既适用于参与该项目的学生，也适用于其他学习高级化学课程的学生。

In this project funded by the Chemical Synthesis Program of the Chemistry Division, Prof. Frank E. McDonald of Emory University is developing the efficient preparation of structurally complex marine natural products, exemplified by brevenal, a non-toxic inhibitor of airborne toxins naturally produced by red tide events in tropical and subtropical marine regions, including the Gulf of Mexico. To decrease the large number of steps required to construct such structurally complex compounds, the research plan addresses this challenge by exploiting a new sequential cyclization strategy for the chemical synthesis of polycyclic ethers, with brevenal as the principal target structure. Broader impacts of this research include a collaborative exercise in which students, including those working on this project, improve their scientific communication skills to better explain to the general public what scientists do, and why what they do is important. Students make short presentations on an ongoing or recently completed research experience, directed to diverse audiences, including an educated adult non-scientist, and an elementary school-age child and receive feedback on presentations by peer students.In order to efficiently prepare fused polycyclic ether natural products, the Emory group is working to harness stereo- and regioselective cascades of ring-forming reactions. The proposed work shifts the paradigm of cascade cyclizations for fused polycyclic ether synthesis from a narrow focus on the difficult endo-mode polyepoxide cyclization, to other cascade cyclization approaches including the exo-mode oxacyclization strategy in this project. The proposed work includes exercises in improving scientific communication skills, both for students working on this project and for other students taking advanced coursework in chemistry.