化学学报 ›› 2025, Vol. 83 ›› Issue (9): 981-986.DOI: 10.6023/A25050159 上一篇    下一篇

研究通讯

醚的α-C—H键氧化/多烯环化串联反应: 一种合成氧杂三环的新方法

左恒昕宇, 虎亚光, 乔霞, 张野*(), 王少华*()   

  1. 兰州大学药学院 天然产物化学全国重点实验室 兰州 730000
  • 投稿日期:2025-05-11 发布日期:2025-06-27
  • 作者简介:

    “中国青年化学家”专辑.

  • 基金资助:
    国家重点研发计划(2023YFA1506404); 国家自然科学基金(22371100); 国家自然科学基金(22401123); 甘肃省科技计划(23ZDFA003); 甘肃省科技计划(24ZDFA003); 甘肃省科技计划(22ZD6FA006); 甘肃省科技计划(23ZDFA015); 甘肃省科技计划(24ZD13FA017); 甘肃省科技计划(24JRRA941); 甘肃省科技计划(23JRRA1144); 甘肃省科技计划(23JRRA1028); 兰州市科技计划(2023-QN-18); 兰州市科技计划(2023-1-17); 兰州市科技计划(2024-1-17); 中央高校基本科研业务专项(lzujbky-2023-ct02); 中央高校基本科研业务专项(lzujbky-2023-pd08); 中央高校基本科研业务专项(lzujbky-2024-17)

An Ether α-C—H Oxidation/Polyene Cyclization Cascade: A Strategy for the Synthesis of Oxatricyclic Scaffolds

Hengxinyu Zuo, Yaguang Hu, Xia Qiao, Ye Zhang*(), Shaohua Wang*()   

  1. State Key Laboratory of Applied Organic Chemistry, School of Pharmacy, Lanzhou University, Lanzhou 730000
  • Received:2025-05-11 Published:2025-06-27
  • Contact: * E-mail: zhang_ye@lzu.edu.cn; wangshh@lzu.edu.cn
  • About author:
    † These authors contributed equally to this work.

    For the VSI “Rising Stars in Chemistry”.

  • Supported by:
    National Key R&D Program of China(2023YFA1506404); National Natural Science Foundation of China(22371100); National Natural Science Foundation of China(22401123); Science and Technology Program of Gansu Province(23ZDFA003); Science and Technology Program of Gansu Province(24ZDFA003); Science and Technology Program of Gansu Province(22ZD6FA006); Science and Technology Program of Gansu Province(23ZDFA015); Science and Technology Program of Gansu Province(24ZD13FA017); Science and Technology Program of Gansu Province(24JRRA941); Science and Technology Program of Gansu Province(23JRRA1144); Science and Technology Program of Gansu Province(23JRRA1028); Lanzhou Science and Technology Planning Project(2023-QN-18); Lanzhou Science and Technology Planning Project(2023-1-17); Lanzhou Science and Technology Planning Project(2024-1-17); Fundamental Research Funds for the Central Universities(lzujbky-2023-ct02); Fundamental Research Funds for the Central Universities(lzujbky-2023-pd08); Fundamental Research Funds for the Central Universities(lzujbky-2024-17)

开发高效通用的多环合成策略是药物化学与有机合成领域的重要挑战. 基于开链醚的α-C—H键氧化/多烯环化串联反应, 成功构建了一系列具有稠合氧杂6/6/6三环骨架的化合物. 该策略通过原位生成高活性的氧鎓离子中间体, 并实现其精准分子内捕获, 从而将简单开链醚前体高效转化为复杂多环体系. 经系统性反应条件优化, 此反应在温和条件下展现出广泛的底物普适性和良好的官能团兼容性. 关键中间体的特定构象和烯烃构型诱导了分子内多烯环化的立体专一性过程, 从而实现了非对映选择性的高效控制.

关键词: C—H键氧化, 多烯环化, 氧鎓离子, 氧杂三环, 串联反应

The development of efficient and general strategies for the construction of polycyclic architectures remains a significant challenge in medicinal chemistry and organic synthesis. In this work, a tandem α-C—H oxidation/polyene cyclization of acyclic ethers that enables the efficient synthesis of a series of fused oxatricyclic 6/6/6 ring systems is developed. This strategy proceeds via the in situ generated highly reactive oxonium ion intermediate, which is selectively intercepted through intramolecular trapping, allowing for the rapid conversion of simple linear ether precursors into complex polycyclic frameworks. Systematic optimization of reaction conditions revealed that the transformation proceeded under mild conditions with broad substrates scope and excellent functional groups tolerance. Under an argon atmosphere, polyenyl acyclic ethers 1 (1.0 equiv.), zinc bromide (10 mol%), TBF4 (2.0 equiv.) and 4Å activated molecular sieve were added to a reaction tube. Subsequently, 1.0 mL of anhydrous 1,2-dichloroethane (DCE) was added as the solvent. The reaction mixture was heated in an oil bath at 70 ℃ for 4 h. Upon completion, the reaction was quenched with saturated aqueous sodium thiosulfate. Then the mixture was extracted with dichloromethane. The organic layers were combined and concentrated under reduced pressure to afford the crude product. The residue was purified by silica gel column chromatography to obtain the cyclized fused oxa-6/6/6-tricyclic architectures 2. Under the optimized conditions, the effects of the ether α-site substituent and terminating aromatic group on the tandem cyclization process were systematically investigated. Remarkably, all substrates underwent efficient cyclization to furnish tricyclic frameworks containing three contiguous stereocenters, achieving yields ranging from moderate to excellent. Notably, the reaction maintained outstanding stereoselectivity, delivering dr>20∶1 in every case examined. According to the proposed mechanism, the specific conformation and the configuration of alkene of key intermediates, combined with the defined geometry of the polyene moiety, induce a highly stereospecific intramolecular cyclization, thereby achieving the efficient diastereoselectivities.

Key words: C—H oxidation, polyene cyclization, oxonium ion, oxatricyclic framework, tandem reaction