Synthesis of 2-substituted benzo[<i>b</i>]thiophenes <i>via</i> gold(<scp>i</scp>)–NHC-catalyzed cyclization of 2-alkynyl thioanisoles
作者:Christopher C. Dillon、Bagieng Keophimphone、Melissa Sanchez、Parveen Kaur、Hubert Muchalski
DOI:10.1039/c8ob02196a
日期:——
developed for the construction of a benzo[b]thiophene core via cyclization reaction of alkynes. Although few catalytic reactions were disclosed, most methods rely on stoichiometric activation of alkynes. Here we report an efficient method for the synthesis of 2-substituted benzo[b]thiophenes from 2-alkynyl thioanisoles catalyzed by a gold(I)–IPr hydroxide that is applicable to a wide range of substrates
苯并[ b ]噻吩杂环是许多重要的小分子药物和候选药物以及有机半导体材料的重要组成部分。已经开发了许多通过炔烃的环化反应来构建苯并[ b ]噻吩核的方法。尽管公开的催化反应很少,但是大多数方法依赖于炔烃的化学计量活化。在这里我们报告了一种由金催化的由2-炔基硫代苯甲醚合成2-取代的苯并[ b ]噻吩的有效方法(I)– IPr氢氧化物,适用于具有多种电子和空间特性的多种底物。另外,我们通过实验证明了酸添加剂及其共轭碱对催化剂周转至关重要。
Regioselective Direct C2 Arylation of Indole, Benzothiophene and Benzofuran: Utilization of Reusable Pd NPs and NHC-Pd@MNPs Catalyst for C–H Activation Reaction
作者:Rajeev V. Hegde、Tiow-Gan Ong、Ram Ambre、Arvind H. Jadhav、Siddappa A. Patil、Ramesh B. Dateer
DOI:10.1007/s10562-020-03390-x
日期:2021.5
A regioselective C2 arylation of indoles, benzothiophene and benzofuran without directing group has been accomplished using economically cheap Pd NPs and NHC-Pd@MNPs catalyst. The reusablecatalyst is efficiently employed to access C2 arylated heterocycles in good to excellent yield. The reusability of the catalyst is studied up to five cycles and a gram-scale synthesis has been achieved. The reaction
A potassium hydroxide/dimethyl sulfoxide (KOH/DMSO) superbase‐promoted method for the synthesis of 2‐substituted benzothiophenes has been developed via photoinduced intermolecular annulation of 2‐halothioanisoles with terminal alkynes at ambient temperature. The present protocol uses commercially available 2‐halothioanisoles as substrates and visible light as energy force, which offers a wide range
first example of near-room-temperature α-arylation of benzo[b]thiophenes is reported. The discovery rests on the observation of a switch in α-/β-regioselectivity at different loadings of Pd2(dba)3·CHCl3 in the coupling between benzo[b]thiophene and 4-iodotoluene. We show that this unprecedented regioselectivity switch is driven by a Ag(I)-mediated C–H activation at the α-C–H position, which becomes the
Selective Palladium-Catalysedipso Arylation of α,α-Disubstituted Benzo[b]thien-2-ylmethanols with Aryl Bromides using PCy3 as Ligand
作者:A. Beatrix Bíró、András Kotschy
DOI:10.1002/ejoc.200600929
日期:2007.3
α,α-Diphenylbenzo[b]thien-2-ylmethanol was treated with a series of arylbromides in the presence of palladium(II) acetate and tricyclohexylphosphane to give the appropriate 2-aryl-benzo[b]thiophenes in good to excellent yield with concomitant formation of benzophenone. The reaction wassuccessfully extended to α,α-diphenylbenzo[b]thien-3-ylmethanol, although in certain cases the transformation was