Boron-Promoted Co-Catalyzed N-Methylation of Secondary Aromatic Amines with CO_(2) and H_(2)  

硼促进Co催化使用CO_(2)和H_(2)实现仲芳香胺N-甲基化

作　　者：Shi Qin Li Zhen He Lin Li Yudong Li Yuehui 石亲;李臻;何林;李玉东;李跃辉(中国科学院兰州化学物理研究所低碳催化与二氧化碳利用国家重点实验室(筹)、羰基合成与选择氧化国家重点实验室,兰州730000;中国科学院大学,北京100049;上海交通大学国家电投智慧能源创新学院,上海200240)

机构地区：[1]State Key Laboratory of Low Carbon Catalysis and Carbon Dioxide Utilization,State Key Laboratory for Oxo Synthesis and Selective Oxidation,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000 [2]University of Chinese Academy of Sciences,Beijing 100049 [3]College of Smart Energy,Shanghai Jiao Tong University,Shanghai 200240

出　　处：《有机化学》2024年第10期3233-3240,共8页Chinese Journal of Organic Chemistry

基　　金：国家自然科学基金(Nos.22022204,22102197);江苏省国家自然基金(Nos.BK20211096,BK20211093)资助项目.

摘　　要：Development of catalytic methods using CO_(2)/H_(2) as methylating reagent for selective methylation of amines is highly attractive.Herein,the methylation of N—H bond via boron promoted activation of Co-formate intermediates is reported.This catalytic system showed excellent functional group tolerance with high catalytic activity,and a series of methylated products were acquired in moderate to excellent yields under mild conditions(e.g.80℃ or 60℃).It was inferred that imine complex C was the crucial intermediate formed via dehydration of species B,providing efficient C—N coupling for the selective N-methylation of secondary aromatic amines with CO_(2)/H_(2).以CO_(2)/H_(2)为新型甲基化试剂,对于发展绿色甲基化方法,建立高效CO_(2)利用新体系具有重要意义.本工作基于硼活化甲酸根钴中间体策略,以爪型三膦配体Triphos原位与Co形成催化剂,实现了温和条件下的N-H甲基化反应.该体系适用于芳香二级胺类底物,并表现出优秀的化学选择性和官能团兼容性,在60~80℃反应条件下,对25个底物反应获得了38%~96%的收率.基于对照实验结果推测,Lewis酸通过B-O相互作用活化甲酸钴物种,接受胺分子的亲核进攻生成物种B,之后脱水生成反应的关键中间体C.

关 键 词：CO_(2)/H_(2) N-METHYLATION cobalt catalysis 

分 类 号：O621.251[理学—有机化学]