Palladium complexes with an annellated mesoionic carbene (MIC) ligand: catalytic sequential Sonogashira coupling/cyclization reaction for one-pot synthesis of benzofuran, indole, isocoumarin and isoquinolone derivatives
作者:Akshi Tyagi、Noor U Din Reshi、Prosenjit Daw、Jitendra K. Bera
DOI:10.1039/d0dt02918a
日期:——
Two Pd(II) complexes (1 and 2) featuring a fused π-conjugated imidazo[1,2-a][1,8]naphthyridine-based mesoionic carbene ligand have been synthesized and structurally characterized. Both complexes effectively catalyze the one-pot synthesis of benzofuran starting from phenylacetylene and 2-iodophenol under mild conditions. Complex 1 is found to be an excellent catalyst for the straightforward access to
合成了两个Pd(II)配合物(1和2),这些配合物具有基于π-共轭咪唑并[1,2- a ] [1,8]萘啶基的介电卡宾配体的稠合结构。两种络合物在温和条件下均能有效地催化苯乙炔和2-碘苯酚的一锅法合成苯并呋喃。通过末端炔烃与苯酚,N-甲基苯胺,苯甲酸和N的2-碘衍生物的反应,发现配合物1是直接访问苯并呋喃,吲哚,异香豆素和异喹诺酮衍生物库的极佳催化剂。-甲基苯甲酰胺。使用多种不同取代的末端炔烃证明了催化方法的通用性,并以良好或优异的收率获得了相应的所需产物。在对照实验的基础上,提出了一种二循环机理,该机理涉及2-碘衍生物与炔烃的Sonogashira偶联以及随后的相应2-炔基化合物的环化。
Cooperation of Mn(III)/Brønsted Acid for the Synthesis of Quindoline Derivatives via Dehydroxylation/Azidation/Cyclization Cascade of Diaryl(1<i>H</i>-indol-2-yl)methanols with Trimethylsilyl Azide
作者:Yu Zhou、Xiao-Ping Xu、Shun-Jun Ji
DOI:10.1021/acs.orglett.9b00164
日期:2019.4.5
A new synthesis of quindoline derivatives promoted by Mn(III)/Brønsted acid via a dehydroxylation/azidation/cyclization cascade of diaryl(1H-indol-2-yl)methanols with trimethylsilyl azide was developed. The reaction features very effective transformation involving two C(sp2)–H and one C(sp3)–O bond cleavages, two C(sp2)–N bonds, and one N-heterocycle formation in a one-pot manner. A series of 11-arylquindolines
A hydroxyl-assisted, organophotoredox/cobaltdual catalyzed annulation of 2-propynolphenols to form 2-hydroxymethyl-benzo[b]furans was developed by employing 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) as photosensitizer and CoCl2(PPh3)2/5,5′-dimethyl-2,2′-bipyridine as cobalt catalytic precursor. Various substrates and functional groups were tolerated. The practical applications of
Electrophilic heterocycles: Functionalization with enol silyl ethers
作者:Grant P. Holmin、Jacob C. Hood、Hongfang Xue、Douglas A. Klumpp
DOI:10.1016/j.tet.2023.133511
日期:2023.8
A series of heterocyclic triaryl methanols were prepared and reacted with enolsilylethers in the presence of ZnCl2. This reaction gave a variety of functionalized heterocyclic products. A mechanism is proposed involving formation triaryl carbocation electrophiles with delocalization of positive charge to positions in the heterocyclic rings. Nucleophilic attack then occurs at a ring position of the