单电子还是双电子?反应底物决定的铁催化未活化烷基卤代物与胺、酰胺和吲哚的酰胺化反应机理  

SET or TET?Iron‐catalyzed aminocarbonylation of unactivated alkyl halides with amines,amides,and indoles via a substrate dependent mechanism

作　　者：艾汉均 赵丰乾 吴小锋 Han‐Jun Ai;Fengqian Zhao;Xiao‐Feng Wu(Leibniz‐Institut für Katalyse e.V.,Albert‐Einstein‐Straße 29a,18059 Rostock,Germany;Dalian National Laboratory for Clean Energy,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,116023 Dalian,Liaoning,China)

机构地区：[1]莱布尼茨催化研究所,德国罗斯托克 [2]中国科学院大连化学物理研究所,辽宁大连116023

出　　处：《Chinese Journal of Catalysis》2023年第4期121-128,共8页催化学报（英文）

基　　金：the Chinese Scholarship Council (CSC) for financial support。

摘　　要：铁廉价,储量丰富,铁基催化剂具有独特的催化活性,其催化的羰基化反应备受化学家关注.烷基溴类化合物具有较高的解离能,酰胺和吲哚类化合物具有弱亲核性,上述性质使其发生羰基化转化具有一定的挑战性.本文发展了一种铁催化的酰胺化反应,使用羰基铁催化剂前体,在反应体系中原位生成低价态的活性铁催化中心,并对烷基类底物进行活化.随后发生一氧化碳对碳铁键的插入、酰基铁的生成、亲核试剂的进攻等反应,最后生成目标产品.在该催化体系作用下,未活化的烷基卤代物可以与胺、酰胺和吲哚发生反应,得到较高收率的酰胺、酰亚胺和N-酰基吲哚等化合物,并表现出较好的官能团兼容性.实验发现,含有天然产物骨架的原料也能够高效转化.在反应机理方面,本文进行了分子内、分子间自由基捕捉等研究,结合已报道的谱学研究结果,推断出低价态铁催化中心的存在.结合实验数据以及反应机理研究结果认为,该反应的反应历程是由底物决定的:当以烷基碘类化合物为原料时,经历的是单电子转移(自由基)过程;当以烷基溴类化合物时,经历的是双电子转移过程.综上,本文发展了一种铁催化的烷基卤代物的酰胺化反应,为烷基酰胺合成提供一定参考.Iron‐catalyzed carbonylation reactions are highly desirable in our sustainability‐advocating chemical community because of its low cost,abundance,and potential for distinct and complementary reactivity patterns.Meanwhile,alkyl bromides as well as low nucleophilic amides and indoles are considered to be particularly challenge substrates for carbonylation reactions.Herein,we report an iron‐catalyzed carbonylative coupling of unactivated alkyl halides with amines,amides,and indoles to assemble amide structural units,affording various amides,imides and N‐acyl indoles with excellent yields and unprecedented functional group compatibility.Remarkably,our approach also represents the example on Fe‐catalyzed aminocarbonylation of alkyl halides.Our preliminary mechanistic studies suggest that the reaction pathway is substrate dependent:the carbonylation proceeds via a radical pathway when alkyl iodides were used;while a two‐electron transfer(TET)process occurred when alkyl bromides served as the electrophiles.

关 键 词：铁催化 羰基化偶联 烷基卤代物 酰胺 酰亚胺 

分 类 号：O621.251[理学—有机化学]