Highly Active Platinum Catalysts for Nitrile and Cyanohydrin Hydration: Catalyst Design and Ligand Screening via High-Throughput Techniques
作者:Xiangyou Xing、Chen Xu、Bo Chen、Chengcheng Li、Scott C. Virgil、Robert H. Grubbs
DOI:10.1021/jacs.8b11667
日期:2018.12.19
Nitrile hydration provides access to amides that are indispensable to researchers in chemical and pharmaceutical industries. Prohibiting the use of this venerable reaction, however, are (1) the dearth of biphasic catalysts that can effectively hydrate nitriles at ambient temperatures with high turnover numbers and (2) the unsolved challenge of hydrating cyanohydrins. Herein, we report the design of
腈水合为化学和制药行业的研究人员提供了必不可少的酰胺。然而,禁止使用这种古老的反应是 (1) 缺乏能够在环境温度下以高转换数有效水合腈类的双相催化剂,以及 (2) 水合氰醇的未解决挑战。在此,我们报告了通过精确地将富电子和缺电子配体相互反式排列,从而增强羟基的亲核性和腈基的亲电性来设计新型“供体-受体”型铂催化剂。利用高通量、自动化的工作流程并评估双齿配体库,我们发现了市售的廉价 DPPF [1,1' -ferrocenendiyl-bis(diphenylphosphine)] 提供优异的反应性。相应的“供体-受体”型催化剂2a很容易由(DPPF)PtCl2、PMe2OH和AgOTf制备。2a 的增强活性允许各种腈和氰醇在 40 °C 下以优异的转化率进行水合。对配体结构的合理重新评估导致发现了改性催化剂 2c,它含有更多富电子的 1,1'-双[双(5-甲基-2-呋喃基)膦基]二茂铁配体