Silacyclopropanes-Building Blocks for Organic Synthesis

尽管三元环化合物在立体选择性有机合成中有许多应用，但硅杂环丙烷并不被认为是合成中间体。 在上一个资助期，我们开发了几个硅环丙烷的碳-碳键形成反应，并证明了它们是立体特异性，立体选择性和区域选择性的。 我们还开发了将产物的碳-硅键转化为碳-氧键的条件，使得硅杂环丙烷将是合成有用的中间体。这一建议扩展了我们的研究silacyclopropane化学，以解决基本问题，包括改进的方法的发展silacyclopropanation，高度官能化和对映体纯的silacyclopropanes的合成，和制备的silacyclopropanes的结构是显着不同的那些研究到目前为止。 我们实验室的初步实验已经暗示了这些问题的解决方案。 我们已经表明，硅环丙烷化发生在热条件下，而不需要高度反应性的试剂。 该反应允许在官能化体系中制备硅杂环丙烷，并且它也可以用于制备纯手性形式的硅杂环丙烷。在资助期间，我们将解决以下硅环丙烷化学中的重要问题：（1）我们将追求立体化学均相，官能化硅环丙烷的合成。 (2)我们将开发分子内硅环丙烷化过程并研究产物的独特反应性。 (3)我们将优化在温和条件下合成硅环丙烷的方法，这将需要设计新的结构硅环丙烷。 (4)我们将开发硅环丙烷的新反应，包括催化的，对映选择性的反应。

Despite numerous applications of three-membered ring compounds in stereoselective organic synthesis, silacyclopropanes were not considered as synthetic intermediates. In the previous funding period, we developed several carbon-carbon bond forming reactions of silacyclopropane, and demonstrated that they were stereospecific, stereoselective, and regioselective. We also developed conditions for conversion of the carbon-silicon bonds of the products into carbon-oxygen bonds so that silacyclopropanes would be synthetically useful intermediates. This proposal extends our studies of silacyclopropane chemistry to address fundamental issues including the development of improved methods for silacyclopropanation, the synthesis of highly functionalized and enantiomerically pure silacyclopropanes, and the preparation of silacyclopropanes with structures that are significantly different from those studied to date. Preliminary experiments from our laboratory have already hinted at solutions to these issues. We have shown that silacyclopropanation occurs under thermal conditions without the need for highly reactive reagents. This reaction allows for the preparation of silacyclopropanes in functionalized systems, and it can also be employed to make silacyclopropanes in homochiral form. During the funding period, we will address the following important issues in silacyclopropane chemistry: (1) We will pursue the synthesis of stereochemically homogeneous, functionalized silacyclopropanes. (2) We will develop intramolecular silacyclopropanation processes and study the unique reactivities of the products. (3) We will optimize methods for the synthesis of silacyclopropanes under mild conditions, which will necessitate devising structurally new silacyclopropanes. (4) We will develop new reactions of silacyclopropanes, including catalytic, enantioselective reactions.