Ni <i>vs.</i> Pd in Suzuki–Miyaura sp<sup>2</sup>–sp<sup>2</sup> cross-coupling: a head-to-head study in a comparable precatalyst/ligand system
作者:Matthew J. West、Allan J. B. Watson
DOI:10.1039/c9ob00561g
日期:——
cornerstone method for sp2–sp2 cross-coupling in industry. There has been a concerted effort to enable the use of Ni catalysis as an alternative to Pd in order to mitigate cost and improve sustainability. Despite significant advances, ligand development for Ni-catalyzed Suzuki–Miyaura cross-coupling remains underdeveloped when compared to Pd and, as a consequence, ligands for Ni-catalyzed processes are typically
The Hiyama Cross‐Coupling Reaction at Parts Per Million Levels of Pd: In Situ Formation of Highly Active Spirosilicates in Glycol Solvents
作者:Shun Ichii、Go Hamasaka、Yasuhiro Uozumi
DOI:10.1002/asia.201901155
日期:2019.11.4
A palladium NNC-pincer complex at a 5 mol ppm loading efficiently catalyzed the Hiyama coupling reaction of aryl bromides with aryl(trialkoxy)silanes in propylene glycol to give the corresponding biaryls in excellent yields. This method was applied to the syntheses of adapalene and a biaryl-type liquid-crystalline compound, as well as to the derivatization of dextromethorphan and norfloxacin. ESI-MS
Pyrazole Synthesis Using a Titanium-Catalyzed Multicomponent Coupling Reaction and Synthesis of Withasomnine
作者:Supriyo Majumder、Kevin R. Gipson、Richard J. Staples、Aaron L. Odom
DOI:10.1002/adsc.200900293
日期:2009.8
coupling of an alkyne, isonitrile, and amine can be used to generate tautomers of 1,3-diimines. These diimines produced in situ undergo cyclization with hydrazine and hydrazine derivatives in a one-pot procedure to provide pyrazoles. Seventeen examples of pyrazoles are provided using this one-pot, 4-component procedure from simple starting materials. The regioselectivity of the alkyne addition can be
complexes were fully characterized by 1H and 13C NMR spectroscopy, electrosprayionizationmassspectrometry (ESI-MS) and elemental analysis. The detailed structures of complexes C1, C2, C5, C6, C9 and C10 were confirmed by single-crystal X-ray diffraction analysis. Moreover, these phosphine–Cu(I) complexes exhibited intense emissions either in the solid state or in solution under UV light excitation. The
杂铜(I)-膦配合物由于结构多样,具有光物理和催化特性而备受关注。在这项工作中,使用设计的联吡啶(L1-L4)和双齿多膦(L5-L8)作为功能性配体,定量合成了一系列杂二亚胺-二膦铜(I)复合物(C1-C10)。这些混合的配体-铜(I)配合物已通过1 H和13 C NMR光谱,电喷雾电离质谱(ESI-MS)和元素分析得到了充分表征。配合物C1,C2的详细结构,C5,C6,C9和C10被单晶X射线衍射分析证实。此外,这些磷化氢– Cu(I)络合物在固态或溶液中在紫外光激发下均表现出强烈的发射。发射复合物C1-C4以猝灭方式(关断)显示出对银离子的高灵敏度发光感测。此外,所有磷化氢保护的铜(I)配合物对水中的叠氮化物-炔烃环加成(CuAAC)都表现出高催化活性。
Cu-catalysed pyrazole synthesis in continuous flow
作者:Júlia Comas-Barceló、Daniel Blanco-Ania、Sebastiaan A. M. W. van den Broek、Pieter J. Nieuwland、Joseph P. A. Harrity、Floris P. J. T. Rutjes
DOI:10.1039/c5cy02247a
日期:——
The synthesis of 1,4-disubstitutedpyrazoles via the cycloaddition reaction of sydnones and terminal alkynes has been achieved employing silica-supported copper catalysts. Furthermore, this methodology has been successfully implemented in continuous flow conditions using prepacked stainless steel cartridges containing the solid-supported copper promoter. Finally, we demonstrate that this synthetic