Expanding Ligand-Metal Bifunctional Catalysis Scope

描述(申请人提供)：SHVO催化剂代表了一类显示配体-金属双功能催化的络合物，提供了独特的反应性多种多样。最近的报告对这些还原的催化循环提供了详细的机理洞察，显示了电子偶联的酸性氢和氢化氢的独特性质。目前，基于不饱和底物的配体-金属双功能催化仅限于加氢反应。该提案概述了用于输送杂原子的类似的Ru络合物的开发。含酸性羟基氢的Ru结合正电杂原子络合物的产生将提供具有前所未有的反应活性的Ru催化剂。这项建议侧重于SHVO催化剂的Ru-B络合物，它有望在极性不饱和底物的氢硼化反应中提供相当于硼阴离子的效果。这种假定的反应性将在合成有机化学中有广泛的应用。本项目的目标是开发不饱和底物上的不对称还原偶联反应。最终，这一方法将扩展到包括更多的杂原子。结合有机合成中成熟的方法，将SHVO催化剂扩展到包括Ru-B络合物，将有助于制备天然产品和药物靶标。值得注意的是，？-杂原子取代的硼酸酯已被用于合成几种天然产物。实现硼烷与高级合成中间体(如复合醛)的不对称还原偶联反应的能力将极大地减少给定合成的步骤数。相关性：在过去的几十年里，将主要基团取代基引入有机底物中受到越来越多的关注，这是因为能够将碳主基键转化为在天然产品和药物靶标中常见的官能团。该项目将允许在复杂的有机分子中引入硼取代基，具有目前技术无法实现的选择性。该方法在合成中具有广阔的应用前景。

DESCRIPTION (provided by applicant): The Shvo catalyst represents a class of complexes that display ligand-metal bifunctional catalysis, providing a unique reactivity manifold. Recent reports have provided detailed mechanistic insight into the catalytic cycle of these reductions displaying the unique nature of the electronically coupled acidic and hydridic hydrogens. Presently, ligand-metal bifunctional catalysis with unsaturated substrates is limited to hydrogenation. This proposal outlines the development of analogous ruthenium complexes for the delivery of heteroatoms. Generation of ruthenium bound electropositive heteroatom complexes containing the acidic hydroxy hydrogen would provide ruthenium catalysts that have unprecedented reactivity. This proposal focuses on ruthenium-boryl complexes of the Shvo catalyst which are expected to provide the equivalent of a boryl anion in the hydroboration of polar unsaturated substrates. This postulated reactivity would have widespread applications in synthetic organic chemistry. The goal of this project is to develop asymmetric reductive coupling reactions of boranes and diboranes with unsaturated substrates. Ultimately, this methodology would be expanded to include additional heteroatoms. In conjunction with well-established methods in organic synthesis, the expansion of the Shvo catalyst to include ruthenium-boryl complexes would be useful in the preparation of natural products and pharmaceutical targets. Notably, ?-heteroatom-substituted boronate esters have been used in the synthesis of several natural products. The ability to achieve asymmetric reductive coupling reactions of boranes to advanced synthetic intermediates (such as a complex aldehyde) would greatly reduce the number of steps of a given synthesis. Relevance: The incorporation of main group substituents into organic substrates have received increasing attention over the past several decades due to the ability to transform the carbon-main group bond into functional groups that are common in natural products and pharmaceutical targets. This project will allow for the introduction of boron substituents into complex organic molecules with selectivities that are not possible with the current technology. This method could have numerous applications in synthesis.