Divergent Synthesis of 1<i>H</i>-Indazoles and 1<i>H</i>-Pyrazoles from Hydrazones<i>via</i>Iodine-Mediated Intramolecular Aryl and<i>sp</i><sup>3</sup>C-H Amination
by condensation of hydrazines with the corresponding ketones. In the presence of potassium iodide, I2-mediated oxidative cyclization of diaryl and tert-butyl aryl ketone hydrazones produced 1H-indazoles via direct aryl C–H amination. Under similar reaction conditions, primary and secondary alkyl ketone hydrazones were transformed into 1H-pyrazole products in a reaction involving sp3 C–H amination. This
Synthesis, Structure, and Reactivity of a Palladium Hydrazonato Complex: A New Type of Reductive Elimination Reaction To Form C−N Bonds and Catalytic Arylation of Benzophenone Hydrazone
A rare, structurally characterized μ1 ,η1 -hydrazonato complex is a probable intermediate in the Pd-catalyzed N-arylation of hydrazones. Starting from aryl halides the reaction proceeds efficiently and under mild conditions with chelating phosphane ligands (L2 ); even Cs2 CO3 can be used as the base [Eq. (a)]. R=alkyl, aryl, MeCO, MeO; X=Br, I.
一种罕见的,结构上的特征μ 1,η 1个-hydrazonato复杂是腙的Pd催化的N-芳基化的可能的中间。从芳基卤化物开始,反应在螯合膦配体(L 2)的温和条件下有效地进行。甚至Cs 2 CO 3也可以用作碱[式。(一种)]。R =烷基,芳基,MeCO,MeO; X = Br,我。
A Palladium-Catalyzed Method for the Preparation of Indoles via the Fischer Indole Synthesis
作者:Seble Wagaw、Bryant H. Yang、Stephen L. Buchwald
DOI:10.1021/ja992077x
日期:1999.11.1
benzophenone hydrazones are converted to indole products via an in situ hydrolysis/Fischer cyclization protocol. A procedure that extends this methodology to the synthesis of N-alkylindoles via the intermediacy of N-aryl-N-alkyl benzophenone hydrazones is described. Additionally, the Pd-catalyzed preparation of diaryl benzophenone hydrazones, followed by a hydrolysis/Fischer cyclization protocol, affords N-arylindole
Industrial-Scale Palladium-Catalyzed Coupling of Aryl Halides and Amines –A Personal Account
作者:Stephen L. Buchwald、Christelle Mauger、Gerard Mignani、Ulrich Scholz
DOI:10.1002/adsc.200505158
日期:2006.1
The palladium-catalyzedcoupling of amines and arylhalides or aryl alcohol derivatives has matured from an exotic small-scale transformation into a very general, efficient and robust reaction during the last ten years. This article reports several applications of this method from an industrial vantage point, including ligand synthesis, synthesis of arylpiperazines, arylhydrazines and diarylamines
<i>peri</i>
‐Xanthenoxanthene (PXX): a Versatile Organic Photocatalyst in Organic Synthesis
作者:Cristofer Pezzetta、Andrea Folli、Oliwia Matuszewska、Damien Murphy、Robert W. M. Davidson、Davide Bonifazi
DOI:10.1002/adsc.202100030
日期:2021.10.19
to be accessible: the β-arylation of cyclic ketones is successful when using a secondary amine as organocatalyst, while cross-coupling reactions of aryl halides with amines and thiols are obtained when using a Ni co-catalyst. Application to the efficient two-step synthesis of the expensive fluoro-tetrahydro-1H-pyrido[4,3-b]indole, a crucial synthetic intermediate for the investigational drug setipiprant
近年来,光催化剂的不断发展,以满足对光氧化还原催化中光物理和氧化还原性能日益增长的需求,设计了复杂的结构或替代策略来获得高度还原或氧化系统。我们在此报告了使用peri- xanthenoxanthene (PXX),一种简单且廉价的染料,作为一种有效的光催化剂。其高度还原的激发态可激活多种底物,从而引发有用的自由基反应。最初证明了基准转换,例如通过有机卤化物的光还原产生的有机自由基添加到自由基陷阱。还显示可以使用更复杂的双催化歧管:β当使用仲胺作为有机催化剂时,环酮的芳基化是成功的,而当使用 Ni 助催化剂时,芳基卤化物与胺和硫醇的交叉偶联反应是成功的。昂贵的氟-四氢-1 H-吡啶并[4,3- b ]吲哚的高效两步合成应用也已得到证实,该吲哚是研究药物塞替吡仑的关键合成中间体。