Iridium complexes for the activation and functionalization of carbon hydrogen-bonds in unactivated substrates

项目摘要 我们提出的研究计划的目标是设计新的催化方法， 通过碳-氢的位点选择性活化合成复杂的有机结构单元 简单有机分子中的键。我们的方法利用一类联吡啶芳基甲烷 作为铱催化的sp3 C-H硼基化催化中的支持配体。这个配体家族是 最近在我们的实验室中确定，并被设计为借用以前的二亚胺和 用于相同转化的五甲基硫配体，同时提供以下优点： 用于其制备的模块化合成路线。我们对这类配体的初步研究确定了一种 目前已知的sp3 C-H硼基化的最佳催化剂，这使我们设计了一个研究 一种利用该系统改进的功能组容差来扩展 合适的衬底的范围。我们拟议的工作将应对 需要sp3 C-H硼基化的选择性，这样做将提供官能化的 具有先前通过C-H不可接近的官能团的烷基硼酸酯产物 activation.进一步应用于合成接头分子和生物学相关的环状 提出了硼酸酯。我们还将探讨联吡啶芳基甲烷配体的应用 到C-H甲硅烷基化催化，这是一类化学反应，基本上是不发达的， 与C-H硼基化相比。 总的来说，该计划以化学方法的形式提供了使能技术， 从简单的前体合成复杂的结构单元。这些方法将使 合成化学家在候选药物和生物探针的合成，通过提供工具， 解决与生物系统接口的分子的必要复杂性。

Project Summary The goal of our proposed research program is the design of new catalytic methodology for the synthesis of complex organic building blocks via site-selective activation of carbon-hydrogen bonds in simple organic molecules. Our approach makes use of a class of dipyridylarylmethanes as supporting ligands in iridium-catalyzed sp3 C-H borylation catalysis. This family of ligands was recently identified in our laboratory and is designed to borrow features of previous diimine and pentamethylcyclopentadienyl ligands for the same transformation while offering the advantage of modular synthetic routes for their preparation. Our initial studies on this ligand class identified one of the best catalysts for sp3 C-H borylation yet known, which has led us to design a research program that takes advantage of the improved functional group tolerance of this system to expand the scope of suitable substrates. Our proposed work will address challenges presented by the need for selectivity in sp3 C-H borylation, and in so doing will provide access to functionalized alkylboronic ester products with functional groups that were previously inaccessible through C-H activation. Further applications to the synthesis of linker molecules and biologically relevant cyclic boronate esters are proposed. We will also explore applications of dipyridylarylmethane ligands to C-H silylation catalysis, a class of chemical reactions that is substantially underdeveloped by comparison to C-H borylation. In total this program provides enabling technologies in the form of chemical methodology for the synthesis of complex building blocks from simple precursors. These methods will empower synthetic chemists in the synthesis of drug candidates and biological probes by providing tools to address the necessary complexity of molecules that interface with biological systems.