BINAP-copper supported by hydrotalcite as an efficient catalyst for the borrowing hydrogen reaction and dehydrogenation cyclization under water or solvent-free conditions
作者:Zhaojun Xu、Xiaoli Yu、Xinxin Sang、Dawei Wang
DOI:10.1039/c8gc00557e
日期:——
A BINAP-Cu system supported by hydrotalcite has been developed and proved to be a highlyefficientcatalyst for the atom-efficient and green borrowing hydrogen reaction and dehydrogenative cyclization. This BINAP-Cu complex supported by hydrotalcite is highly air-stable and can be recycled at least five times under solvent-free conditions. Notably, 1-benzyl-2-aryl-1H-benzo[d]imidazole derivatives could
已经开发了由水滑石支撑的BINAP-Cu系统,并被证明是一种高效的催化剂,用于原子效率高的绿色借入氢反应和脱氢环化反应。这种由水滑石负载的BINAP-Cu络合物具有高度的空气稳定性,在无溶剂条件下可以循环至少五次。值得注意的是,第一次以水为溶剂仅一步即可由醇合成1-苄基-2-芳基-1 H-苯并[ d ]咪唑衍生物。这为在水或无溶剂条件下以高收率合成官能化的胺,酮和1-苄基-2-芳基-1 H-苯并[ d ]咪唑衍生物提供了一种更加绿色有效的催化方法。
Nickel-catalysed dehydrogenative coupling of aromatic diamines with alcohols: selective synthesis of substituted benzimidazoles and quinoxalines
The first nickel-catalysed dehydrogenative coupling of primary alcohols and ethylene glycol with aromaticdiamines for selective synthesis of mono- and di-substituted benzimidazoles and quinoxalines is reported. The earth-abundant, non-precious and simple NiCl2/L1 system enables the synthesis of N-heterocycles releasing water and hydrogen gas as byproducts. Mechanistic studies involving deuterium labeling
Tunable Triazole-Phosphine-Copper Catalysts for the Synthesis of 2-Aryl-1<i>H</i>
-benzo[d]imidazoles from Benzyl Alcohols and Diamines by Acceptorless Dehydrogenation and Borrowing Hydrogen Reactions
作者:Zhaojun Xu、Duo-Sheng Wang、Xiaoli Yu、Yongchun Yang、Dawei Wang
DOI:10.1002/adsc.201700179
日期:2017.10.4
activity. Mechanistic studies and deuterium labeling experiments indicated that the reactions proceeded by an initial and reversible alcohol dehydrogenation resulting in a copper hydride intermediate. This was also supported by the direct observation of a diagnostic copper hydride signal by solid‐state infrared spectroscopy. The TAP−Cu‐H complex showed absorptions at 912 cm−1 that could be assigned
三唑-膦-铜配合物(TAP-Cu)已被合成并用作可调谐和有效的催化剂,用于选择性合成氟代2-芳基-1 H-苯并[d]咪唑和1-苄基-2-芳基1小时一步法制得的简单醇中的苯并[d]咪唑衍生物。TAP-Cu对脱氢和借用氢反应均显示出优异且可调节的催化活性,首次证明了80多个例子。观察到配体在催化剂活性中起关键作用。机理研究和氘标记实验表明,反应是通过初始且可逆的醇脱氢进行的,从而生成氢化铜中间体。固态红外光谱法直接观察氢化铜诊断信号也支持了这一点。TAP-Cu-H络合物在912 cm -1处显示吸收可以分配给氢化铜拉伸。此外,也成功地进行了中间双亚胺的直接捕集。
Heterogenizing a Homogeneous Nickel Catalyst Using Nanoconfined Strategy for Selective Synthesis of Mono- and 1,2-Disubstituted Benzimidazoles
homogeneous Ni-phenanthroline catalyst was successfully immobilized into the cavities of a metal–organic framework, ZIF-8. The as-synthesized heterogeneous catalyst, Ni-Phen@ZIF, represents the first MOF based catalyst that enables dehydrogenative coupling of alcohols with aromatic diamines for selectivesynthesis of both mono- and 1,2-disubstituted benzimidazoles. The catalyst survived under harsh basic