Palladium-Catalyzed Decarboxylative Acylation of<i>O</i>-Phenyl Carbamates with α-Oxocarboxylic Acids at Room Temperature
作者:Satyasheel Sharma、Aejin Kim、Eonjeong Park、Jihye Park、Minyoung Kim、Jong Hwan Kwak、Sang Hwi Lee、Young Hoon Jung、In Su Kim
DOI:10.1002/adsc.201200993
日期:2013.3.11
A palladium‐catalyzed oxidative acylation of O‐phenyl carbamates with α‐oxocarboxylic acids via selective aromatic CH bond activation is described. This protocol represents the first ortho‐acylation of phenol derivatives, and a catalytic amount of triflic acid additive is crucial for this transformation.
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
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。
Room-temperature Pd-catalyzed C–H chlorination by weak coordination: one-pot synthesis of 2-chlorophenols with excellent regioselectivity
作者:Xiuyun Sun、Yonghui Sun、Chao Zhang、Yu Rao
DOI:10.1039/c3cc47431c
日期:——
A room-temperature Pd(II)-catalyzed regioselective chlorination reaction has been developed for a facile one-pot synthesis of a broad range of 2-chlorophenols. The reaction demonstrates an excellent regioselectivity and reactivity for CâH chlorination. This reaction represents one of the rare examples of mild CâH functionalization at ambient temperature.
Ruthenium-catalyzed oxidative C–H alkenylation of aryl carbamates
作者:Jie Li、Christoph Kornhaaß、Lutz Ackermann
DOI:10.1039/c2cc36196e
日期:——
A cationic ruthenium(II) catalyst enabled highly efficient oxidative alkenylations of electron-rich arenes bearing removable, weakly coordinating carbamates, and allowed for cross-dehydrogenative CâH bond functionalization in an aerobic manner.