SYNTHESIS OF UNIQUE BORACYCLIC SYSTEMS

建议合成的中环和大环化合物的一般方面： 合成化学家面临的一个重要挑战是中间体的构建 和大环环系统。在本申请的第1部分中建议的是 我们的预想贡献使用的是所谓的“硼模板” 合成“。建议：(A)评估 通过氢化/羰化或类似物形成双环碳硼烷 杂原子取代三烯基片的工艺研究。(B)该硼循环 然后在影响碎片化(Grob)的条件下进行治疗 生成含有中等尺寸环的烯烃杂环(硼= 杂原子)。最后(C)，性质和综合效用，通过 将对这些硼环中的硼进行替代研究。 倍半萜(Pacifigorgo1)的全合成 铆接的立体化学。使用“硼”的一个重要优势 模板“合成策略是有充分证据和可预测的化疗-， 氢化硼对聚烯烃的区域和立体选择性 底物。产生我们这个阶段的最重要的问题是 提案涉及羰化反应的立体化学。 (一氧化碳/氰化/碳负离子插入/等)。为了解决这个问题，我们 提出了用硼环(缝合和环合)法合成紫花果 铆接)，C-1羟基1基团的立体化学从 引人入胜的一步。根据可用的少量数据，我们正在 预测由一环硼环烷形成环氧丙烷 羰化反应或类似的过程。我们将探讨这样一种可能性 铆接技术的变化可能会改变立体化的结果 换硼工艺。这一全合成的一个主要目标是 介绍更多关于碳-硼替代过程的见解。

General aspects of proposed synthesis of Medium and Macrocyclic Compounds: An important challenge to synthetic chemists is the construction of medium and macrocyclic ring systems. Proposed in Part 1 of this application is our envisioned contribution using what is termed "Boron Template Synthesis". It is proposed to: (A) Assess the synthetic potential of forming bicyclic carboranes via hydroboration/carbonylation or equivalent process of heteroatom substituted triene substrates. (B) This boracycle will then be treated under conditions that effect fragmentation (Grob) to yield olefinic heterocycles containing a medium size ring (boron = heteroatom). Finally (C), the properties and synthetic utility, through replacement of Boron, of these boracycles will be investigated. Sesquiterpene (Pacifigorgo1) Total Synthesis: A Look at the Stereochemistry of Riveting. An important advantage in using the "Boron Template" synthetic strategy is the well documented and predictable chemo-, regio- and stereoselectivitiy of boron hydrides towards polyolefinic substrates. The overriding question which has generated this phase of our proposal deals with the stereochemistry of carbonylation (CO/cyanidation/carbanion insertion/etc.). To address this problem we propose the synthesis of pacifigorgo via Boron Annulation (stitching and riveting), the stereochemistry of the C-1 hydroxy1 group evolving from the riveting step. Based on the small amount of data available, we are predicting the formation of pacifigorgol from a boracyclane via carbonylation or equivalent process. We will explore the possibility that variations in riveting techniques might alter the stereochemical outcome of the boron replacement process. A major goal of this total synthesis is to present more insight into this carbon boron replacement process.