Palladium/Norbornene Cooperative Catalysis To Access Tetrahydronaphthalenes and Indanes with a Quaternary Center
Palladium/Norbornene Cooperative Catalysis To Access Tetrahydronaphthalenes and Indanes with a Quaternary Center
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DOI：
10.1021/acscatal.8b00975
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发表时间：
2018-06-01
期刊：
影响因子：
12.9
通讯作者：
Zhou, Qianghui
中科院分区：
文献类型：
--
作者：
Liu, Ze-Shui;Qian, Guangyin;Zhou, Qianghui
开发了一种包含钯/XPhos络合物和5-降冰片烯-2-羧酸的协同催化体系。该系统促进双组分环化反应，允许通过连续的Catellani型C-H活化和氧化还原中继Heck反应构建含有四级中心的四氢萘和茚满。廉价的 5-降冰片烯-2-羧酸在此过程中充当催化介体 (20 mol%)。这种温和、可扩展的化学选择性方案与多种现成的芳基碘化物和烷基化试剂兼容。演示了该方法在阿片类镇痛药依他佐辛的四步合成中的应用。初步研究强调了使 Catellani/氧化还原中继 Heck 级联具有对映选择性的未来前景。
A cooperative catalytic system comprising a palladium/XPhos complex and 5-norbornene-2-carboxylic acid was developed. This system promotes a two-component annulation reaction, allowing the construction of tetrahydronaphthalenes and indanes that contain quaternary centers through consecutive Catellani-type C-H activation and redoxrelay Heck reaction. Inexpensive 5-norbornene-2-carboxylic acid acts as a catalytic mediator (20 mol %) in this process. This mild, scalable, and chemoselective protocol is compatible with a wide variety of readily available aryl iodides and alkylating reagents. Application of this method in a 4-step synthesis of opioid analgesic eptazocine is demonstrated. Preliminary studies underscore the future promise of rendering this Catellani/redox-relay Heck cascade enantioselective.