STRATEGIES FOR CLEAVING THE C-C BOND OF OXIRANES

环氧乙烷将被用作更大的氧杂环化合物的前体， 吡喃类、氧杂环庚烯类和氧杂环辛烯类， 涉及环氧化物的碳-碳键的断裂。 这 将使用几种策略来完成转化， 包括环氧化物的四碳环膨胀为 氧杂环庚三烯通过（3，3）σ迁移重排和均裂 通过自由基或双自由基中间体的键断裂。 净 这些转变的效果是插入一个氧原子 变成碳碳双键 在制定这些战略时， 将有足够的机会探索反应途径， 以前没有被利用过，甚至可能没有被观察到。 本研究项目的长期目标是应用 化学描绘在这个建议，以合成天然 具有生物学意义的产品，含有中等大小的 氧杂环，如线性稠环系统的氧杂环， 短杆菌毒素和氧杂双环骨架的单端孢霉烯 倍半萜

Oxiranes will be used as precursors to larger oxacycles such a pyrans, oxepins, and oxocines through novel strategies that involve the rupture of the carbon-carbon bond of an epoxide. This transformation will be accomplished using several strategies, including the four-carbon ring expansion of an epoxide to an oxepin via (3,3) sigmatropic rearrangement and the homolytic bond cleavage via radical or biradical intermediates. The net effect of these transformations is the insertion of an oxygen atom into a carbon-carbon double bond. In developing these strategies there will be ample opportunity to explore reaction pathways that have not previously been exploited or possibly even observed. The long-term goal of this research project is to apply the chemistry delineated in this proposal to the synthesis of natural products of biological interest that contain medium-sized oxacycles, such as the linearly fused ring systems of the brevetoxins and the oxabicyclic skeleton of the tricothecene sesquiterpenes.