【作者】 邢思洋；

【导师】 王忠文；

【作者基本信息】 南开大学 ， 农药学， 2012， 博士

【摘要】 杂原子桥环骨架和中环骨架广泛存在于天然产物中，是两种重要的生物活性骨架。建立这两类骨架结构多样性的分子库对筛选相关结构新农药先导和新医药先导有着非常重要的作用。尤其近年来新农药的研究创制往往依赖于简单结构先导化合物的发现，基于复杂环系结构的新农药先导并不多见。复杂环系结构先导化合物具有结构新颖、易于修饰等特点，开展这类研究将对新农药的发展有着积极的促进意义。有机合成化学家在过去的一百多年历史中，已经发展了大量的构筑这两类环系的方法。近年来随着一些有重要生理活性的天然产物如platensimycin、cortistatin A、englerin A等不断的被分离得到，杂原子桥环骨架的构筑方法及其相关天然产物全合成仍旧是有机合成领域的热门话题。环加成反应尤其是分子内环加成反应，具有较高的成键效率、容易反应和良好的区域、立体选择性等特点，在复杂环系的构筑中扮演着重要的角色。我们的研究希望基于张力环烷烃与碳杂原子双键的分子内交叉环加成反应，发展通用高效的杂原子桥环的构筑方法，同时通过杂原子桥环化合物的开环反应，也实现中环骨架的构筑。首先我们发展了1,1-二酯基环丙烷与羰基和碳氮双键的分子内交叉[3+2]环加成反应，实现了氧杂/氮杂-[n.2.1](n=2,3,4)桥环骨架的通用高效构筑，并将这一构筑方法学成功应用于platensimycin的形式全合成中。我们也应用这一方法学所构筑的杂原子桥环化合物，进行了开环反应的研究，通过三步反应，最终成功实现了中环化合物的构筑。其次，我们发展了单给单拉电子环丙烷与羰基的分子内交叉[3+2]环加成反应，这一方法学所构筑的氧杂/氮杂-[n.2.1](n=2,3,4)桥环骨架含有缩酮结构，经历还原开环反应一步就可以给出中环化合物。我们也成功的应用这一方法实现了komaroviquinone四环核心骨架的合成。再次，我们将1,1-二酯基环丙烷与碳氮双键的分子内交叉[3+2]环加成反应尝试应用于生物活性分子PHT的构筑。最后，我们也发展了1,1-二酯基环丁烷与羰基的分子内交叉[4+2]环加成反应，实现了氧杂-[3.3.1]桥环骨架的构筑。更多还原

【Abstract】 Heteroatom bridged skeletons and medium rings, which are widelydistribured in natural products, are two important kinds of biologicalactive skeletons. Building the structural diversity of molecule libraries forthese two skeletons has a very important role on screening novelpesticide and medicine lead compounds of related structure. In particular,the research and creatment of novel pesticides often depends on thediscovery of simple lead compounds in recent years, but the leadcompounds containing complex cyclic structure are relatively rare.Starting the related research has a positive impact on the development ofnovel pestiides because of novel structure and easy modification of thecomplex lead compounds. In the past100years, synthetic organicchemists have developed a large number of methodologies forconstruction of the two skeletons. With the isolation of several important biological acive natural products such as platensimycin, cortistatin A andenglerin A in recent years, the methodologies for construction ofheteroatom bridged skeletons and the total synthesis of relatived naturalproducts is still a hot topic. Cycloadditions, espically the intramolecularcycloadditions, play an important role in the synthesis of complex cyclicskeletons because of excellent bonding efficiency, easy reactivecharacteristic and good regioslectivity and stereoslectivity. We hope thatwe could develop general and efficient methodologies for construction ofheteroatom bridged skeletons based on the intramolecularcross-cycloadditions of the strained cycloalkanes with thecarbon-heteroatom double bonds. Meanwhile, we also hope to completethe construction of medium rings through the ring-opening reaction ofheteroatom bridged compounds.Firstly, we have developed intramolecular [3+2] cross-cycloadditionsof1,1-diester cyclopropanes with carbonyls and the carbon-nitrogen double bonds. These reactions provided general and efficient strategiesfor construcitions of oxa/aza-[n.2.1](n=2,3,4) bicyclic skeletons andwere successfully used to the formal total synthesis of platensimycin. Theheteroatom bridged compounds were also successfully explored toprovide the medium rings by a three-steps ring-opening reaction.Secondly, we have developed intramolecular [3+2] cross-cycloadditionsof mono-donor mono-acctepor cyclopropanes with carbonyls. Becausethe oxa-[n.2.1](n=2,3,4) bicyclic skeletons by this method contain thestructure of ketal, medium-ring compounds could be obtained by onlyone-step reductive ring-opening reaction. This method was alsosuccessfully used to the synthesis of the core skeletons ofkomaroviquinone. Thirdly, intramolecular [3+2] cross-cycloadditions of1,1-diester cyclopropanes with the carbon-nitrogen double bonds wastried to complete the total synthesis of PHT. At last, we developedintramolecular [4+2] cross-cycloadditions of1,1-diester cyclobutanes with carbonyls, successfully completing the construction of oxa-[3.3.1]bicyclic skeletons.These intramolecular cross-cycloadditions, which are catalyzed byLewis acid, all proceed on mild reaction conditions and have the broadscope of the substrates. They build a solid foundation for theestablishment of dibersity molecular libraries of heteroatom bridgedskeletons and medium rings and the discovery of novel pesticide leadcompounds.更多还原