Catalyzed Coupling of Organostannanes with Electrophiles

复杂分子的合成需要开发 灵敏、经济的新试剂。在有机的补助金 和高分子化学计划支持研究导致 新的催化方法，将促进合成的 新一代抗生素的特点是 复杂的立体化学相互关系。 本研究的目的是探索综合有用的 利用有机锡的钯催化的偶联反应 试剂和有机亲电试剂作为偶联配偶体。 一 研究的目标是开发一种不对称的 其中在偶联时产生手性碳的合成 通过使用光学活性的过渡金属催化剂， 为了实现这些目标，机械的理解 有机锡试剂如何将有机基团转移到 将寻求有机钯（II）卤化物。 transmetabolism 各种有机锡试剂与烷基钯（II）的反应 带有反式螯合膦配体的卤化物将被 进行，以使transmethalo产物不能经历 还原消除 合成几何纯的（E或Z）乙烯基三氟甲磺酸酯和 它们与有机锡烷的偶联反应， 乙烯基锡烷，将探索在努力合成 含有共轭二烯的化合物， 各种生物活性产品结构特征， 包括从花生四烯酸衍生的某些共轭多烯 酸 将探索芳基三氟甲磺酸酯的偶联反应， 以及芳基三氟甲磺酸酯和芳基卤化物与 乙烯基锡烷将被开发用于合成许多 吲哚生物碱 用于偶联的其它有用的亲电试剂，例如 因为将寻求乙烯基环氧化物和α-卤代羰基化合物， 扩大反应的范围。 有效运用 一些未经测试的锡试剂应该提供新的合成 各种产品的途径，包括一些 拟除虫菊酯 这种偶联化学在本领域中的应用 还将开发应变环化合物的合成。

The synthesis of complex molecules requires the development of sensitive, cost-effective new reagents. This grant in the Organic and Macromolecular Chemistry Program supports research leading to new catalytic processes that will facilitate synthesis of the new generation of antibiotics that are characterized by extremely complex stereochemical interrelationships. It is the object of this research to explore synthetically useful palladium-catalyzed coupling reactions utilizing an organotin reagent and an organic electrophile as coupling partners. One goal of the research is the development of an asymmetric synthesis in which a chiral carbon is generated at the coupling site by the use of optically active transition metal catalysts. In order to attain these objectives, a mechanistic understanding of how an organotin reagent transfers an organic group to an organopalladium(II) halide will be sought. The transmetallation reactions of various organotin reagents with alkylpalladium(II) halides bearing a trans-chelating phosphine ligand will be carried out such that the transmetallation product cannot undergo reductive elimination. The synthesis of geometrically pure (E or Z) vinyl triflates and their coupling reactions with organostannanes, particuarly vinylstannanes, will be explored in an effort to synthesize compounds containing the conjugated dienes, an important structural feature in a variety of biologically active products, including certain conjugated polyenes derived from arachadonic acid. The coupling reactions of aryl triflates will be explored, and the reactions of both aryl triflates and aryl halides with vinylstannane will be developed for the synthesis of a number of indole alkaloids. Other useful electrophiles for coupling, such as vinyl epoxides and alpha-halocarbonyls will be sought in order to expand the scope of this reaction. The effective use of a number of untested tin reagents should provide new synthetic pathways to a variety of products including a number of pyrethoids. The utilization of this coupling chemistry in the synthesis of strained ring compounds also will be developed.