Intermolecular amidation of unactivated sp2 and sp3 C-H bonds via palladium-catalyzed cascade C-H activation/nitrene insertion
Intermolecular amidation of unactivated sp2 and sp3 C-H bonds via palladium-catalyzed cascade C-H activation/nitrene insertion
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DOI：
10.1021/ja062856v
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发表时间：
2006-07-19
影响因子：
15
通讯作者：
Che, Chi-Ming
中科院分区：
文献类型：
--
作者：
Thu, Hung-Yat;Yu, Wing-Yiu;Che, Chi-Ming
本通讯描述了Pd（OAc）2催化的未活化的sp2和sp 3C-H键的分子间酰胺化反应，使用伯酰胺和过硫酸钾。含有侧基肟或吡啶基团的底物被酰胺化，具有优异的化学选择性和区域选择性。值得注意的是，反应性的C-X键被很好地耐受，并且各种伯酰胺可以是Pd催化的C-H酰胺化反应的有效亲核试剂。对于未活化的sp 3C-H键的反应，优选1° sp 3C-H键相对于2° C-H键的β-酰胺化。催化反应是由螯合辅助的环钯化反应引发的，涉及C-H键活化。初步的机理研究表明，过硫酸盐氧化伯酰胺应产生反应性氮烯物种，然后与环钯配合物反应。
This communication describes the Pd(OAc)2-catalyzed intermolecular amidation reactions of unactivated sp2and sp3C−H bonds using primary amides and potassium persulfate. The substrates containing a pendent oxime or pyridine group were amidated with excellent chemo- and regioselectivities. It is noteworthy that reactive C−X bonds were well-tolerated and a variety of primary amides can be effective nucleophiles for the Pd-catalyzed C−H amidation reactions. For the reaction of unactivated sp3C−H bonds, β-amidation of 1° sp3C−H bonds versus 2° C−H bonds is preferred. The catalytic reaction is initiated by chelation-assisted cyclopalladation involving C−H bond activation. Preliminary mechanistic study suggested that the persulfate oxidation of primary amides should generate reactive nitrene species, which then reacted with the cyclopalladated complex.