Copper-Catalyzed, Aerobic Oxidation of Hydrazone in a Three-Phase Packed Bed Reactor
Copper-Catalyzed, Aerobic Oxidation of Hydrazone in a Three-Phase Packed Bed Reactor
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DOI：
10.1021/acs.oprd.1c00165
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发表时间：
2021-07-22
影响因子：
3.4
通讯作者：
Jones, Christopher W.
中科院分区：
文献类型：
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作者：
Hatridge, Taylor A.;Wei, Bo;Jones, Christopher W.
在连续三相流动反应器中实现铜催化的需氧腙氧化以产生合成上有用的重氮化合物，其具有完全转化和高选择性，这是通过将先前公开的分批方法适应于本文所述的流动系统并进行参数空间探索以优化工艺条件来实现的。该方法的稳健性得到证明，完全的腙转化率和90%的稳态重氮化合物选择性保持超过11个停留时间。在有限范围的二铑（II）催化的卡宾反应的上游采用重氮合成证明了该方法在生成用于环加成和活化的二级C-H插入反应的按需重氮化合物中的实用性。据我们所知，所得到的过程代表了第一次报道的流动中的腙氧化催化过程。此外，该方法仅产生水作为氧化副产物，是对先前在流动中合成重氮化合物的非催化尝试的改进，其产生化学计量量的废物。与处理反应性重氮化合物相关的安全危害的增加的可持续性和减轻可以使该方法适合于实际应用。
Copper-catalyzed, aerobic hydrazone oxidation to produce synthetically useful diazo compounds is achieved in a continuous, three-phase flow reactor with complete conversion and high selectivity by adapting a previously published batch methodology to a flow system described herein and conducting a parameter space exploration to optimize the process conditions. The robust nature of the process is demonstrated, with complete hydrazone conversion and a 90% steady-state diazo compound selectivity maintained over 11 residence times. Employing the diazo synthesis upstream of a limited scope of dirhodium(II)-catalyzed carbene reactions demonstrates the utility of this process in generating on-demand diazo compounds for cycloaddition and activated secondary C-H insertion reactions. The resulting process represents, to the best of our knowledge, the first reported catalytic process for hydrazone oxidation in flow. Additionally, this process, which only generates water as an oxidative byproduct, is an improvement over previous noncatalytic attempts to synthesize diazo compounds in flow, which generate stoichiometric amounts of waste. The increased sustainability and mitigation of safety hazards associated with handling reactive diazo compounds may make this approach suitable for practical applications.