Copper-catalyzed [2+3]-annulation of N–H imines with vinyl azides: access to polyaryl 2<i>H</i>-imidazoles
作者:Zhongzhi Zhu、Hanze Lin、Baihui Liang、Junjie Huang、Wanyi Liang、Lu Chen、Yubing Huang、Xiuwen Chen、Yibiao Li
DOI:10.1039/c9cc10042c
日期:——
A practical method for the synthesis of 2H-imidazoles via a [2+3] annulation of N-H imines with vinylazides using a copper catalyst is developed. In this conversion, environmentally friendly oxygen is used as the sole oxidant and N2 and H2O are the only by-products. The catalytic transformation, operating under mild conditions, is operationally simple and is considered as a readily available catalytic
作者:Charles Brown、B. Terence Grayson、Robert F. Hudson
DOI:10.1039/p29790000427
日期:——
The free energies of Z–E isomerisation of a wide range of symmetrical N-sulphenylimines have been measured at the coalescence temperature by a 1H n.m.r. procedure. In two cases the rate of isomerisation of unsymmetrical N-sulphenylimines at a series of temperatures has been measured and activation enthalpies and entropies determined. The effect of substituents on the isomerisationbarrier ΔG* has been
已通过1 H nmr程序在聚结温度下测量了各种对称N-磺基苯亚胺的Z - E异构化的自由能。在两种情况下,已经测量了在一系列温度下非对称N-磺苯基亚胺的异构化速率,并确定了活化焓和熵。取代基对异构化势垒ΔG的影响*可以通过氮孤对与亚胺碳和氮上取代基的超共轭转化来解释,该取代以线性转变态用于转化过程。使用扩展的Hückel扰动方法以轨道方式讨论了结果,该方法可用于定性地解释取代基对广泛的亚氨基化合物(包括胍和亚氨基碳酸酯)的反转势垒的影响。
Hydrogen bond directed aerobic oxidation of amines <i>via</i> photoredox catalysis
An application of H-bonding interactions for directing the α-C–H oxidation of amines to amides and amino-ketones catalyzed by an organic photocatalyst is reported. The high efficiency of this method is demonstrated by the aerobic oxidation of pyrrolidines, diarylamines and benzylamines bearing urea groups with high yields and a wide substrate scope.
A nickel-catalyzed protocol for the conversion of aryl and heteroaryl alcohol derivatives to primary and secondary aromaticamines via C(sp2)–O bond cleavage is described. The new amination protocol can be applied to a range of substrates bearing diverse functional groups and uses readily available benzophenone imines as an effective nitrogen source.
Light‐Driven Enantioselective Synthesis of Pyrroline Derivatives by a Radical/Polar Cascade Reaction
作者:Ricardo I. Rodríguez、Leonardo Mollari、José Alemán
DOI:10.1002/anie.202013020
日期:2021.2.23
functionalization of acyl heterocycles through a hydrogen‐atom transfer (HAT) process and the use of tailor‐made ketimines as reliable electrophilic partners. This transformation is translated into an enantiomerically controlled radical/polar cascade reaction in which water is produced as the sole by‐product and stereoselectivity is dictated by coordination to a chiral‐at‐rhodium catalyst.