DIVALENT GERMANIUM AND TIN IN ORGANIC SYNTHESIS

有机合成中的二价锗和锡

• 批准号: 3467767
• 负责人: ERIC J ROSKAMP
• 金额: $ 13.24万
• 依托单位: NORTHWESTERN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-02-08 至 1996-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3467767
• 关键词: alcohols; aldehydes; alkenes; chemical synthesis; diazo compound; diol; epoxides; esters; germanium; imines; ketones; stereochemistry; stereoisomer; tin

Our specific aim is to construct functionalized organic molecules which are substructures of biologically relevant compounds. The assemblage of complex molecules under mild, selective, and stereocontrolled conditions are challenging goals. These criteria can be met by the discriminating reactivity and unique structural features of divalent germanium or tin. These elements hare three chemical features; small bond angels, an empty p orbital, and a lone pair of electrons. These properties will be used to develop new carbon-carbon bond forming reagents and procedures. We are pursuing three synthetic methods towards these goals; i) The synthesis of a new class of compounds that would serve as optically active, diastereoselective, alpha-alkoxy-anion synthons: germanium (II) epoxides. After they have been prepared, we will examine their insertion reactions with unsaturated organic substrates. For example, the addition of an aldehyde to a germanium (II) epoxide would stereoselectively form a vicinal diol, or the addition of an imine would yield a 1,2-amino alcohol. ii) The synthesis of functionalized organoketones via the SnC12 catalyzed addition of diazo compounds to aldehydes. These products contain highly versatile functional groupings that readily lend themselves to further synthetic transformations. For example, the addition of ethyl diazoacetate to an aldehyde exclusively yields a beta-keto ester, under very mild conditions. iii) The synthetic application of intramolecular insertion reactions leading to stereocontrolled rearrangements or olefin inversions. Bromohydrins are readily obtained form olefins (trans addition mechanism). Treating them with a germanium (II) reagent may induce a syn elimination to take place thus resulting in a net inversion of olefin geometry.

我们的具体目的是构建功能化的有机分子 生物学相关化合物的子结构。 组合 在轻度，选择性和立体控制条件下的复杂分子 是具有挑战性的目标。 这些标准可以通过歧视 二价锗或锡的反应性和独特的结构特征。 这些元素野鸡三个化学特征；小邦德天使，一个空的p 轨道和一对孤独的电子。 这些属性将用于 开发新的碳碳键形成试剂和程序。 我们是 追求三种综合方法朝向这些目标； i）合成 一类新的化合物，可以作为光学活动， 非映选择性，α-烷氧基 - 氨基合成子：锗（II）环氧化物。 准备后，我们将检查他们的插入反应 与不饱和有机基材。 例如，添加 醛向锗（II）环氧化物的醛将立体选择性形成餐具 Diol或添加亚胺会产生1,2-氨基醇。 ii） 通过SNC12催化加法的官能化有琴酮的合成 将重氮化合物与醛的化合物。 这些产品包含高度的用途 功能分组很容易借给自己进一步合成 转型。 例如，在 醛在非常轻微的条件下仅产生β-酮酯。 iii）分子内插入反应的合成应用 导致立体控制的重排或烯烃倒置。 溴氢蛋白很容易获得烯烃（反式添加机制）。 用锗（II）试剂对其进行治疗可能会引起Syn outivilition 因此发生，导致烯烃几何形状的净反转。