New Cycloadditions in Synthesis

描述：(申请人提供)独一无二的化学品介绍 转化可以极大地缩短医学上的合成途径 重要的化合物。众所周知，环加成反应特别有效。 用于构建高度复杂的分子的反应。这样做的目的是 建议开发和使用环丁二烯的新的环加成反应。会的 证明了高度官能化的环丁烯通过 分子内环丁二烯环加成反应可以提供一个通用的平台 用于快速进入复杂的分子系统。尤其是在与 其他关键的转变，分子的复杂性和结构的应变 环加合物为高效地构建 中环天然产物，具有耐人寻味的生物活性。 环丁烯环加成物将用于制备环庚烷 以及含环辛烷的产品。分子间和分子内 环丁烯的环丙烷化反应，然后是选择性的碳-碳键 碎片，将被用于有效地生成所发现的5-7环系统 在众多具有生物活性的天然产品中。同样，a(2+2) 光环化/碎片化策略将提供通往5-8-5环的途径 系统。化学在合成化合物中的简明应用 详细介绍了二萜类化合物，如甘露醇。 简而言之，开发合成环丁二烯的新路线的组合 配合物，研究这些配合物的新的环加成反应，以及 展示环加合物在中环合成中的应用将 为构建具有生物学意义的分子提供了更好的机会。

DESCRIPTION: (provided by applicant) The introduction of unique chemical transformations can considerably shorten synthetic pathways toward medicinally important compounds. Cycloadditions are known to be especially powerful reactions for building molecules of high complexity. The objectives of this proposal are to develop and use new cycloadditions of cyclobutadiene. It will be shown that highly functionalized cyclobutenes generated through intramolecular cyclobutadiene cycloadditions can provide a versatile platform for rapid entry into complex molecular systems. In particular, when used with other key transformations, the molecular complexity and structural strain of the cycloadducts offer unique opportunities for the efficient construction of medium ring-containing natural products with intriguing biological activities. The cyclobutene cycloadducts will be used in the preparation of cycloheptanoid and cyclooctanoidcontaining products. Inter- and intramolecular cyclopropanations of the cyclobutenes, followed by selective carbon-carbon bond fragmentations, will be used to generate effectively the 5-7 ring system found in numerous biologically active natural products. Similarly, a (2+2) photocyclization/fragmentaton strategy will provide access to the 5-8-5 ring system. Concise applications of the chemistry toward the synthesis of diterpenes, such as kalmanol, are detailed. In short, the combination of developing new routes toward cyclobutadiene complexes, investigating novel cycloadditions of these complexes, and demonstrating the utility of the cycloadducts in medium ring synthesis will offer improved opportunities for building molecules of biological significance.