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A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis
Journal of Visualized Experiments Pub Date : 2020-02-16 , DOI: 10.3791/60441
Alexander Rosen , Kara Lindsay , Andrew Quillen , Quynh Nguyen , Matthew Neiser , Stephen Ramirez , Stefana Costan , Nathan Johnson , Thuy Donna Do , Lili Ma

Heteroarylation introduces heteroaryl fragments to organic molecules. Despite the numerous available reactions reported for arylation via transition metal catalysis, the literature on direct heteroarylation is scarce. The presence of heteroatoms such as nitrogen, sulfur and oxygen often make heteroarylation a challenging research field due to catalyst poisoning, product decomposition and the rest. This protocol details a highly efficient direct α-C(sp3) heteroarylation of ketones under microwave irradiation. Key factors for successful heteroarylation include the use of XPhos Palladacycle Gen. 4 Catalyst, excess base to suppress side reactions and the high temperature and pressure achieved in a sealed reaction vial under microwave irradiation. The heteroarylation compounds prepared by this method were fully characterized by proton nuclear magnetic resonance spectroscopy (1H NMR), carbon nuclear magnetic resonance spectroscopy (13C NMR) and high-resolution mass spectrometry (HRMS). This methodology has several advantages over literature precedents including broad substrate scope, rapid reaction time, greener procedure and operational simplicity by eliminating the preparation of intermediates such as silyl enol ether. Possible applications for this protocol include, but are not limited to, diversity-oriented synthesis for the discovery of biologically active small molecules, domino synthesis for the preparation of natural products and ligand development for new transition metal catalytic systems.

中文翻译:

微波辅助过渡金属催化的酮类直接杂芳基化

杂芳基化将杂芳基片段引入有机分子。尽管报道了许多通过过渡金属催化进行芳基化的可用反应,但有关直接杂芳基化的文献很少。氮,硫和氧等杂原子的存在,由于催化剂中毒,产物分解及其他原因,常常使杂芳基化成为具有挑战性的研究领域。该协议详细介绍了微波辐射下酮的高效直接α-C(sp3)杂芳基化反应。成功进行杂芳化的关键因素包括使用XPhos Palladacycle Gen.4催化剂,过量的碱来抑制副反应以及在微波辐射下密封反应瓶中获得的高温和高压。通过质子核磁共振波谱(1H NMR),碳核磁共振波谱(13C NMR)和高分辨率质谱(HRMS)充分表征了通过该方法制备的杂芳基化合物。该方法相对于文献先例具有多个优势,包括广泛的底物范围,快速的反应时间,更绿色的步骤以及通过消除中间体(如甲硅烷基烯醇醚)的制备而简化的操作。该协议的可能应用包括但不限于:发现生物活性小分子的面向多样性的合成,用于制备天然产物的多米诺骨牌合成以及用于新型过渡金属催化系统的配体开发。碳核磁共振波谱(13C NMR)和高分辨率质谱(HRMS)。该方法相对于文献先例具有多个优点,包括广泛的底物范围,快速的反应时间,绿色的方法以及通过消除中间体(如甲硅烷基烯醇醚)的制备而简化的操作。该协议的可能应用包括但不限于:用于发现生物活性小分子的面向多样性的合成,用于制备天然产物的多米诺骨牌合成以及用于新型过渡金属催化系统的配体开发。碳核磁共振波谱(13C NMR)和高分辨率质谱(HRMS)。该方法相对于文献先例具有多个优势,包括广泛的底物范围,快速的反应时间,更绿色的步骤以及通过消除中间体(如甲硅烷基烯醇醚)的制备而简化的操作。该协议的可能应用包括但不限于:发现生物活性小分子的面向多样性的合成,用于制备天然产物的多米诺骨牌合成以及用于新型过渡金属催化系统的配体开发。通过消除中间体(如甲硅烷基烯醇醚)的制备,可实现更绿色的过程和操作简便性。该协议的可能应用包括但不限于:发现生物活性小分子的面向多样性的合成,用于制备天然产物的多米诺骨牌合成以及用于新型过渡金属催化系统的配体开发。通过消除中间体(如甲硅烷基烯醇醚)的制备,可实现更绿色的过程和操作简便性。该协议的可能应用包括但不限于:发现生物活性小分子的面向多样性的合成,用于制备天然产物的多米诺骨牌合成以及用于新型过渡金属催化系统的配体开发。
更新日期:2020-02-16
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