Aryl Nitriles from Alkynes Using <i>tert</i>-Butyl Nitrite: Metal-Free Approach to C≡C Bond Cleavage
作者:Uttam Dutta、David W. Lupton、Debabrata Maiti
DOI:10.1021/acs.orglett.6b00147
日期:2016.2.19
AlkyneC≡Cbond breaking, outside of alkyne metathesis, remains an underdeveloped area in reaction discovery. Recently, nitrogenation has been reported to allow nitrile formation from alkynes. A new protocol for the metal-free C≡Cbondcleavage of terminal alkynes to produce nitriles is reported. This method provides an opportunity to synthesize a vast range of nitriles containing aryl, heteroaryl
Catalytic Activation of Trimethylsilylacetylenes: A One-Pot Route to Unsymmetrical Acetylenes and Heterocycles
作者:Dániel Lasányi、Ádám Mészáros、Zoltán Novák、Gergely L. Tolnai
DOI:10.1021/acs.joc.8b00998
日期:2018.8.3
the synthesis of unsymmetrical acetylenes, a Sonogashira coupling–deprotection–Sonogashira coupling reaction sequence is often used. Removal of protecting groups requires harsh conditions or an excess of difficult to handle and expensive reagents. Herein, we disclose a novel catalytic method for the selective deprotection of trimethylsilylacetylenes in Sonogashira reaction. The reagent hexafluorosilicic
M-CPOnes: transition metal complexes with cyclopropenone-based ligands for light-triggered carbon monoxide release
作者:Marc Lehr、Tjorge Neumann、Christian Näther、Anna J. McConnell
DOI:10.1039/d2dt00835a
日期:——
cyclopropenone-based ligands for CO release with the modular scaffold of transitionmetalcomplexes. In proof-of-concept studies, M-CPOnes based on ZnII, FeII and CoII are stable in the dark but undergo light-triggered CO release with the cyclopropenone substituents and metal ions enabling tuning of the photophysical properties. Furthermore, the choice of metal allows the use of different spectroscopic methods
一种新型的 CO 释放分子 M-CPones 是结合用于释放 CO 的环丙烯酮配体与过渡金属配合物的模块化支架制备的。在概念验证研究中,基于 Zn II、Fe II和 Co II的 M-CPOnes在黑暗中稳定,但通过环丙烯酮取代基和金属离子进行光触发的 CO 释放,从而可以调节光物理性质。此外,金属的选择允许使用不同的光谱方法来监测从荧光光谱到紫外/可见光谱和顺磁核磁共振光谱的光脱羰。M-CPOnes 从金属离子到环丙烯酮取代的模块化以及配体进一步功能化的潜力使得 M-CPOnes 对应用中的定制功能具有吸引力。
Designing New Magnesium Pincer Complexes for Catalytic Hydrogenation of Imines and <i>N</i>-Heteroarenes: H<sub>2</sub> and N–H Activation by Metal–Ligand Cooperation as Key Steps
difficulty in heterolytic cleavage of the H–H bond. Employing aromatization/de-aromatization metal–ligand cooperation (MLC) highly enhances the H2 activationprocess, offering an efficient approach for the hydrogenation of unsaturated molecules catalyzed by main-group metals. Herein, we report a series of new magnesium pincer complexes prepared using PNNH-type pincerligands. The complexes were characterized
利用主族金属替代过渡金属进行均相催化成为近年来的研究热点。然而,由于H-H键的异裂解困难,它们在催化氢化中的应用较少。采用芳构化/去芳构化金属-配体合作 (MLC) 可显着增强 H 2活化过程,为主族金属催化的不饱和分子氢化提供了一种有效的方法。在此,我们报告了一系列使用 PNNH 型钳配体制备的新型镁钳络合物。通过核磁共振和 X 射线单晶衍射对配合物进行了表征。H 2的可逆激活开发了使用这些钳形络合物的 MLC 的 N-H 键。使用新的镁配合物,实现了醛亚胺和酮亚胺的均匀催化氢化,以优异的收率提供仲胺。对照实验和 DFT 研究表明,涉及 MLC 的途径有利于氢化反应。此外,该高效催化扩展到喹啉和其他N-杂芳烃的选择性加氢,首次展示了早期主族金属配合物均相催化N-杂芳烃加氢的实例。该研究为镁化合物催化的C=N键加氢提供了新的策略,丰富了主族金属催化的研究。
Direct Synthesis of α-Trifluoromethyl Ketone from (Hetero)arylacetylene: Design, Intermediate Trapping, and Mechanistic Investigations
作者:Arun Maji、Avijit Hazra、Debabrata Maiti
DOI:10.1021/ol502071g
日期:2014.9.5
Regioselective addition across the alkynes has been achieved in a silver-catalyzed protocol utilizing Langlois reagent (CF3SO2Na) and molecular O2 to access medicinally active α-trifluoromethyl ketone compounds. This method was successful in producing α-trifluoromethyl ketone in heterocyclic scaffolds, which are incompatible with earlier strategies. Experimental findings suggest a mechanism involving α-styrenyl radical intermediate and 1-methyl-2-pyrrolidinone (NMP) solvent, which leads to crystallographically characterized N-methylsuccinimide. Isotope labeling, kinetic studies, and intermediate trapping further helped to gain insight into this energy-demanding process.