o-Bromophenylzinc compound: a readily available and efficient synthetic equivalent of o-phenylene 1-anion 2-cation
摘要:
An o-bromophenylzinc compound, first prepared in an excellent yield by the reaction of o-bromoiodobenzene with zinc powder in THF, was found to be an efficient synthetic equivalent of o-phenylene 1-anion 2-cation in Pd(O)-catalyzed stepwise cross-coupling reactions, affording unsymmetrically 12-disubstituted benzenes with diverse substitution patterns and with a variety of functional groups. (C) 1998 Elsevier Science Ltd. All rights reserved.
Enantioselective Folding of Enynes by Gold(I) Catalysts with a Remote <i>C</i><sub>2</sub>-Chiral Element
作者:Giuseppe Zuccarello、Joan G. Mayans、Imma Escofet、Dagmar Scharnagel、Mariia S. Kirillova、Alba H. Pérez-Jimeno、Pilar Calleja、Jordan R. Boothe、Antonio M. Echavarren
DOI:10.1021/jacs.9b06326
日期:2019.7.31
Chiral gold(I) catalysts have been designed based on a modified JohnPhos ligand with a distal C2-2,5-diarylpyrrolidine that creates a tight binding cavity. The C2-chiral element is close to where the C-C bond formation takes place in cyclizations of 1,6-enynes. These chiral mononuclear catalysts have been applied for the enantioselective 5-exo-dig and 6-endo-dig cyclization of different 1,6-enynes
作者:Allegra Franchino、Àlex Martí、Antonio M. Echavarren
DOI:10.1021/jacs.1c11978
日期:2022.3.2
data, and studies of solvent and nonlineareffects substantiate the key H-bonding interaction at the heart of the catalytic system. This conceptually novel approach, which lies at the intersection of metal catalysis, H-bond organocatalysis, and asymmetric counterion-directed catalysis, provides a blueprint for the development of supramolecularly assembled chiral ligands for metal complexes.
3-Substituted 2-bromobiphenylenes were brominated to give benzocyclooctene or 7(8H)-benzocyclooctenone derivatives, but not biphenyl derivatives. The structure of 5,8,10-tribromo-7(8H)-benzocyclooctenone was determined by X-ray diffraction analysis.
3-取代的 2-溴联苯被溴化得到苯并环辛烯或 7(8H)-苯并环辛酮衍生物,但不是联苯衍生物。5,8,10-tribromo-7(8H)-benzocyclooctenone 的结构由 X 射线衍射分析确定。
Fine-tuning hydroxylamines as single-nitrogen sources for Pd(0)-catalyzed diamination of o-bromo(or chloro)-biaryls
Transition metal-catalyzed diamination by hydroxylamines is a common approach for making three-membered aziridines, while its use for building the larger N-heterocycles is still underdeveloped. Herein, we report an efficient Pd(0)-catalyzed inter-molecular [4+1] annulation of o-bromo(or chloro)-biaryls with bifunctional secondary hydroxylamines for the one-step assembly of synthetically useful carbazoles
羟胺的过渡金属催化二化是制备三元氮丙啶的常用方法,而其用于构建较大的N-杂环的用途仍未开发。在此,我们报告了一种有效的 Pd(0) 催化的分子间 [4+1] 环化邻溴(或氯)-联芳基与双功能仲羟胺,用于一步组装合成有用的咔唑。值得注意的是,这种多米诺骨牌反应的关键是明智地选择氨基源和 Pd(0)-催化剂,以便在具有不稳定 NO 的羟胺存在下将芳基卤化物氧化加成到 Pd(0)-物种中。键。
Ni(II) catalyzed bromination of aryl C–H bonds
作者:Moumita Bhattacharya、David B. Cluff、Siddhartha Das
DOI:10.1016/j.ica.2014.08.012
日期:2014.11
Bromination of unactivated aromatic C-H bonds without directing and/or chelating groups was achieved by employing an air stable N-heterocyclic Ni(II) complex. PhI(OAC)(2) and N-bromosuccinimide have been used as the oxidizing agent and the bromine source, respectively. Yields for bromination are as high as >99%, especially in presence of electron-withdrawing groups like -NO2 and -CF3. This is a rare report on C-H bond activation with Ni(II) where, instead of homo C-C coupling, reductive elimination to form C-halogen could be achieved. (C) 2014 Elsevier B.V. All rights reserved.