无光敏剂参与的可见光诱导咪唑并[1,2-a]吡啶的三氟甲基化反应  

Photosensitizer-Free Visible-Light-Promoted Trifluoromethylation of Imidazo[1,2-a]pyridines

作　　者：姚瑞超 陈文博 沈其龙[2,3] Yao Ruichao;Chen Wenbo;Shen Qilong(Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power,Shanghai University of Electric Power,Shanghai 200090;CAS Key Laboratory of Organofluorine Chemistry,Center for Excellence in Molecular Synthesis,Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences,Shanghai 200032;University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]上海电力大学上海市电力材料防护与新材料重点实验室,上海200090 [2]中国科学院上海有机化学研究所分子合成卓越中心中国科学院有机氟化学重点实验室,上海200032 [3]中国科学院大学,北京100049

出　　处：《有机化学》2021年第7期2684-2692,共9页Chinese Journal of Organic Chemistry

基　　金：国家自然科学基金(No.21625206);中国科学院战略性先导科技专项(B类)(No.XDB20000000);上海市自然科学基金(No.20ZR1471600);上海市科学技术委员会(No.19DZ2271100)资助项目.

摘　　要：发展了一个无光敏剂参与的可见光促进的咪唑并[1,2-a]吡啶衍生物的三氟甲基化新反应.该反应利用本课题组此前发展的基于硫叶立德骨架的亲电三氟甲基化试剂作为三氟甲基自由基源,反应条件温和,底物普适性好,同时兼容常见的官能团.机理研究表明该反应可被自由基捕获剂阻断.对两个反应底物及它们的1∶1混合物的紫外-可见光吸收光谱进行了研究,研究表明三氟甲基化试剂与咪唑并[1,2-a]吡啶之间形成了一个Donor-Acceptor加合物.在此基础上提出了一个合理的机理,即该加合物在光照条件下被激发,发生硫-三氟甲基键均裂生成三氟甲基自由基,该自由基与咪唑并[1,2-a]吡啶发生自由基取代反应.同时也成功地将该方法应用于治疗胃溃疡药物佐利米定的三氟甲基化衍生物的合成.A photosensitizer-free visible-light-promoted method for direct trifluoromethylation of imidazo[1,2-a]pyridine derivatives using an electrophilic trifluoromethylating reagent based on sulfonium ylide skeleton was described.The reaction occurred in broad substrate scope under mild conditions and tolerant various functional groups.Initial mechanistic experiments including reactions in the presence of radical scavengers and UV absorption spectroscopic studies were conducted.Inhibition by the radical scavengers were observed.In addition,an extra-absorption peak between 500~510 nm in UV-Vis absorption spectrum was observed.These observations led us to propose a working mechanism.Finally,application of the current method for the preparation of trifluoromethylated derivative of gastroproctive drug zolimidine was demonstrated.

关 键 词：三氟甲基 可见光 无光敏剂 咪唑并[1 2-a]吡啶 

分 类 号：TQ460.1[化学工程—制药化工]