Copper porphyrin-catalyzed construction of ether bond by cross-dehydrogenative coupling of sp [3] C–H bond with phenols bearing electron-withdrawing groups (EWG) was described for the first time. A broad range of substrates afforded different acetals in moderate to excellent yields with good functional group tolerance. The developed method is not only suitable for phenol substrates with ortho-directing
The construction of C(sp<sup>3</sup>)–O bond via copper porphyrin catalyzed cross-dehydrogenative coupling reaction: Substituent and electronic effect of the catalysts
effect of copper porphyrin catalysts on the cross-dehydrogenativecoupling (CDC) reaction between the hydroxyl group of phenol substrates and C(sp3)-H bond have been investigated. Results showed that copper porphyrin bearing electron-withdrawing, bulky steric hindrance or heteroatom of pyridyl groups could increase the catalytic activity in the reaction. 5,10,15,20-(tetrakis(4-pyridyl)porphyrin)copper
Copper
<scp>porphyrin‐catalyzed</scp>
C(sp
<sup>2</sup>
)
<b>—</b>
O bond construction via coupling phenols with formamides
作者:Shuang Yang、Xiao‐Yan Chen、Ming‐Feng Xiong、Hao Zhang、Lei Shi、Dong‐Zi Lin、Hai‐Yang Liu
DOI:10.1002/jccs.202100046
日期:2021.8
construction of C(sp2)—Obond via coupling formamides with phenols was achieved firstly. A broad range of substrates afforded various carbamates in moderate to good yields with good functional group tolerance at low catalyst loading. Intermolecular competing kinetic isotope effect experiment indicated that the generation of formamide radical is the rate-determining step of current cross-dehydrogenative coupling
Nickel-Catalyzed Efficient and Practical Suzuki−Miyaura Coupling of Alkenyl and Aryl Carbamates with Aryl Boroxines
作者:Li Xu、Bi-Jie Li、Zhen-Hua Wu、Xing-Yu Lu、Bing-Tao Guan、Bi-Qin Wang、Ke-Qing Zhao、Zhang-Jie Shi
DOI:10.1021/ol9029534
日期:2010.2.19
Suzuki−Miyaura coupling of unactivated alkenyl carbamates is described to construct polysubstituted olefins. The developed process is also suitable for heteroaromatic and even electron-richaromatic carbamates.
Palladium Catalyzed C–H Functionalization of <i>O</i>-Arylcarbamates: Selective <i>ortho</i>-Bromination Using NBS
作者:Alex John、Kenneth M. Nicholas
DOI:10.1021/jo300713h
日期:2012.7.6
cis-coordination of the amine. However, the amine adducts failed to undergo ortho-amination (C–N bond formation) under varied reaction conditions. Notably, the palladacycle 1d was found to react efficiently with N-iodosuccinimide (NIS) to yield the ortho-iodinated carbamate, 1e. More significantly, this reaction can be extended to a palladium-catalyzed ortho C–H bromination of aryl-O-carbamates even at 5 mol %
通过使各自的氨基甲酸酯与Pd(OAc)2在酸,CF 3 CO 2 H,CF 3 SO 3 H和p -TsOH存在下反应,合成了一系列衍生自O-苯基氨基甲酸酯的环金属化钯配合物。观察到palladacycles能配位胺和富电子的苯胺,但不能配位磺酰胺或羧酰胺。通过NMR光谱法(NOE)分析palladacycle 2b(2b · t Bu-NH 2)的t Bu-NH 2加合物显示出一种顺式-胺的配位。但是,在不同的反应条件下,胺加合物均无法进行邻氨基化(C–N键形成)。值得注意的是,发现palladacycle 1d与N-碘琥珀酰亚胺(NIS)有效反应,生成邻碘代氨基甲酸酯1e。更重要的是,即使在使用N-溴代琥珀酰亚胺(NBS)的Pd(OAc)2负载为5 mol%的情况下,该反应也可以扩展为钯催化的芳基-O-氨基甲酸酯的邻位C-H溴化反应。