Development of New Cascade Sequences for the Construction of Novel Chemical Structures

有机合成计划支持王功教授的研究， 西弗吉尼亚大学的新级联反应序列， 到新型化学结构的构建。 反应顺序 基于烯二炔和烯炔-联烯的环芳构化，包括 （Z）-3-己烯-1，5-二炔和（Z）-1，2，4-庚三烯-6-炔，导致 多环碳框架，而类似的环化 烯炔-烯酮，烯炔-烯酮亚胺，烯炔-异氰酸酯，和 烯炔-双酰亚胺提供了获得新的多环杂环的途径。 二烯二炔的级联电环化提供了反应性的 苯并环丁二烯，其不寻常的多环二聚体代表 含有多个二苯并环辛四烯的化合物的合成条目 单位 烯二联烯的环化导致形成 邻醌二甲烷和潜在的发现新的合成 雌酮和四环结构的途径构成了 天然二萜的数量。 许多自然界的生物活性化合物显示出复杂的分子结构， 结构，以及这些化合物的尝试合成，无论是用于 结构阐明的目的，稀缺的大规模生产 天然存在的化合物，或下一代 合成类似物，需要不断开发新的策略 来处理它们的分子复杂性。 通过利用不寻常的 缺电子前体分子的环化反应， 王教授开发了各种简单的合成路线， 含有全碳原子的多环分子结构， 环内含有氮和氧原子的化合物 结构. 这些环化反应在它们自身的性质中是重要的。 从化学的角度， 重要的是关于有机结构和反应性。 此外，反应化学提供了合成途径， 公认的和新的化学结构，提供新的合成路线 用于制备类固醇如雌酮以及其它 四环结构是一类天然存在的 被称为二萜的化合物。

The Organic Synthesis Program supports Professor Kung Wang's studies at the University of West Virginia of new cascade reaction sequences leading to the construction of novel chemical structures. Reaction sequences based on the cycloaromatization of enediynes and enyne-allenes, including (Z)-3-hexene-1,5-diynes and (Z)-1,2,4-heptatriene-6-ynes, lead to polycyclic carbon frameworks, while analogous cyclizations of enyne-ketenes, enyne-ketenimines, enyne-isocyanates, and enyne-carbodiimides afford access to novel polycyclic heterocycles. Cascade electrocyclizations of dienediynes provide reactive benzocyclobutadienes, the unusual polycyclic dimers of which represent synthetic entry to compounds containing multiple dibenzocyclooctatetraene units. Cyclizations of enediallenes lead to the formation of o-quinodimethanes and to the potential discovery of novel synthetic routes to estrone and tetracyclic structures forming the basis of a number of naturally-occurring diterpenes. Many of Nature's biologically active compounds display complex molecular structures, and the attempted synthesis of such compounds, whether for purposes of structure elucidation, large-scale production of scarce naturally occurring compounds, or preparation of next-generation synthetic analogs, requires the continuing development of new strategies to deal with their molecular complexity. By exploiting unusual cyclization reactions of electron-deficient precursor molecules, Professor Wang develops facile synthetic routes to a wide variety of polycyclic molecular structures containing all-carbon atoms as well as compounds containing nitrogen and oxygen atoms within their cyclic structures. These cyclization reactions are significant in their own right from a chemical perspective, addressing issues of fundamental importance with regards to organic structure and reactivity. Additionally, the reaction chemistry provides synthetic access to both recognized and novel chemical structures, affording new synthetic routes for the preparation of steroids such as estrone as well as other tetracyclic structures characteristic of a class of naturally-occurring compounds known as the diterpenes.