Palladium-Catalyzed Aerobic Dehydrogenation of Carbon-Carbon Bonds

钯催化碳-碳键有氧脱氢

• 批准号: 8221784
• 负责人: Shannon S Stahl
• 金额: $ 27.67万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8221784
• 关键词: Address; Aerobic; Aldehydes; Alder plant; Alkenes; Amides; Benign; Carbon; Catalysis; Complement; Coupling; Cyclohexanones; Development; Diels Alder reaction; Esters; Family; Hydrogen; Hydrogen Bonding; Investigation; Ketones; Lead; Ligands; Mediating; Metals; Methods; Molecular; Natural regeneration; Nitrogen; Organic Chemistry; Organic Synthesis; Oxidants; Oxygen; Palladium; Pattern; Pharmacologic Substance; Phenols; Physical condensation; Play; Positioning Attribute; Preparation; Process; Production; Reaction; Research; Role; Route; Site; Solvents; Structure; System; Therapeutic Agents; Water; Work; carbonyl compound; carbonyl group; catalyst; cycloaddition; cyclohexene; dehydrogenation; novel; oxidation; pyridine; quinoline; single bond

DESCRIPTION (provided by applicant): The research outlined in this proposal targets a new class of "C-H functionalization" reactions, involving Pd-catalyzed dehydrogenation of aliphatic carbon-carbon single bonds to form aromatic, heteroaromatic and alkene products. These reactions should have widespread utility in the synthesis of pharmaceuticals and biologically active molecules. This novel reactivity will build upon recent advances in aerobic oxidation catalysis to enable molecular oxygen to serve as the stoichiometric oxidant/hydrogen acceptor, forming of water as the sole byproduct of the reaction. Empirical studies directed toward the development of new Pd catalysts and investigation of their synthetic applications will be complemented by systematic mechanistic studies to establish the fundamental principles that contribute to successful reactivity. Four different classes of reactions are targeted: (1) dehydrogenation of cyclohexanones and cyclohexenones to prepare a variety of substituted phenol derivatives, (2) dehydrogenation of ketones and other carbonyl compounds to prepare versatile 1,2-unsaturated carbonyl compounds, (3) dehydrogenation of cyclohexenes to prepare a variety of substituted arenes, and (4) dehydrogenation of 6-membered nitrogen heterocycles to prepare quinoline and pyridine derivatives. Substrates for these reactions can be obtained from readily available starting materials via a number of versatile synthetic routes, including Diels-Alder cycloadditions, Robinson annulations, and simple condensation and addition reactions. Key steps in these dehydrogenation reactions include PdII-mediated activation of a C-H bond, often from a relatively activated site (e.g., adjacent to a carbonyl group or in an allylic position), to form a PdII- alkyl intermediate, followed by 2-hydride elimination to produce the unsaturated product and a PdII-hydride intermediate. Oxidation of the PdII-H species by molecular oxygen regenerates the active PdII catalyst. The identification of new ligands for the Pd catalysts will play an important role in this work because the ligands are critical to modulate the reactivity of PdII in the reactions involving the organic substrate and to stabilize the reduced forms of Pd (Pd0 and PdII-H) in the catalyst reoxidation process. Overall, the development of efficient new catalysts for aerobic dehydrogenation of C-C bonds, together with the ease of synthetic access to diverse organic substrates for these reactions, will provide environmentally benign routes to selectively substituted aromatic and heteroaromatic compounds that rival or surpass the utility of some of the most powerful synthetic transformations in organic chemistry, such as metal-catalyzed cross-coupling reactions. PUBLIC HEALTH RELEVANCE: The development of efficient methods for the synthesis of organic molecules is critical for the discovery, development and commercial production of pharmaceuticals and therapeutic agents. The research outlined in this proposal will lead to new catalytic methods for the preparation of such biologically active molecules.

描述（由申请人提供）：该提案中概述的研究针对新的“ C-H功能化”反应，涉及脂肪族碳碳单键的PD催化脱氢，形成芳族，异源和烯烃产物。这些反应在制药和生物活性分子的合成中应该具有广泛的效用。这种新颖的反应性将基于有氧氧化催化的最新进展，使分子氧作为化学计量氧化剂/氢受体，形成水作为反应的唯一副产品。系统的机械研究将补充针对新的PD催化剂和合成应用的研究，以建立有助于成功反应性的基本原理。针对四种不同类别的反应：（1）环己酮和环己烯酮的脱氢作用，以制备各种取代的苯酚衍生物，（2）酮和其他羰基化合物的脱氢作用，以使多功能1,2-无含量的碳纤维化合物和（3）变种的脱水量（3）cycynexexecy的脱水（3）的脱水量的脱水，（3） （4）6元的氮杂环的脱氢作用以制备喹啉和吡啶衍生物。这些反应的底物可以通过多种多功能合成路线（包括Diels-Alder Cycloaditions，Robinson Annaunity，Robinson Annerations以及简单的凝结和添加反应）从随时可用的起始材料中获得。 这些脱氢反应的关键步骤包括PDII介导的C-H键激活，通常来自相对激活的位点（例如，与羰基或烯丙基位置相邻），形成PDII-烷基中间体，以形成2-氢化物，然后消除2-HydriDe，以产生不饱和的产品和一个不饱和的产品和pdii-hy-hydide IntermedipersimedipersimedIntermediredipersimedIntermediredipersimed inspride intermedipersimed intermide inspride inspride intermediredipersimed inspride inspride intermediredipersimed。通过分子氧对PDII-H物种氧化可再生活性PDII催化剂。 PD催化剂的新配体的鉴定将在这项工作中发挥重要作用，因为配体对于调节涉及有机基质的反应中PDII的反应性至关重要，并且在催化剂重新氧化过程中PD（PD0和PDII-H）的还原形式（PD0和PDII-H）稳定。 Overall, the development of efficient new catalysts for aerobic dehydrogenation of C-C bonds, together with the ease of synthetic access to diverse organic substrates for these reactions, will provide environmentally benign routes to selectively substituted aromatic and heteroaromatic compounds that rival or surpass the utility of some of the most powerful synthetic transformations in organic chemistry, such as metal-catalyzed cross-coupling reactions. 公共卫生相关性：开发有机分子合成的有效方法对于药物和治疗剂的发现，开发和商业生产至关重要。该提案中概述的研究将导致用于制备这种生物活性分子的新催化方法。