Rhodium-Catalyzed Dehydrogenative Coupling of Phenylheteroarenes with Alkynes or Alkenes
摘要:
Benzo-fused tri- to heptacyclic heteroarenes were effectively constructed by the rhodium-catalyzed dehydrogenative coupling of phenylheteroarenes with alkynes. Using alkenes as coupling partners, dehydrogenative alkenylation took place selectively on the phenyl moiety of phenylheteroarenes. Several experiments with deuterium-labeled substrates indicated that double C-H bond cleavages take place even in the reaction with alkenes.
Oxidative Biaryl Coupling of Thiophenes and Thiazoles with Arylboronic Acids through Palladium Catalysis: Otherwise Difficult C4-Selective CH Arylation Enabled by Boronic Acids
It adds up to 4! Thiophenes and thiazoles can be arylated in the 4‐ rather than the expected 5‐position in a new CH functionalization reaction (see scheme; TEMPO: 2,2,6,6‐tetramethylpiperidine‐N‐oxyl). The boronicacid proved to be the key to achieving the otherwisedifficult C4 selectivity. The method was applied to a concise synthesis of a key pharmacological structure with potential for treatment
less‐reactive β position of thiophenes was previously inaccessible to direct functionalization. However, the β selectivity observed with the catalytic system PdCl2/POCH(CF3)2}3/Ag2CO3 in the arylation of thiophenes with iodoarenes (see scheme) is a remarkably general phenomenon applicable to unsubstituted, monosubstituted, and disubstituted thiophene derivatives, as well as thiophene‐containing fused aromatic
开放获取:通常无法直接将噻吩的反应性降低的噻吩的β位置进行直接功能化。但是,在噻吩与碘代芳烃的芳基化反应中,催化体系PdCl 2 / P OCH(CF 3)2 } 3 / Ag 2 CO 3所观察到的β选择性是一种显着的普遍现象,适用于未取代的,单取代的,和二取代的噻吩衍生物,以及含噻吩的稠合芳族化合物。
Pd/C as a Catalyst for Completely Regioselective CH Functionalization of Thiophenes under Mild Conditions
作者:Dan-Tam D. Tang、Karl D. Collins、Johannes B. Ernst、Frank Glorius
DOI:10.1002/anie.201309305
日期:2014.2.10
The completely C3‐selective arylation of thiophenes and benzo[b]thiophenes was achieved by using Pd/C as a heterogeneous catalyst without ligands or additives undermild reaction conditions. The practicability of this transformation is demonstrated by notable functional group tolerance and the insensitivity of the reaction to H2O and air. This method is also applicable to nitrogen‐ and oxygen‐containing
通过在温和的反应条件下使用Pd / C作为不带配体或添加剂的非均相催化剂,可以实现噻吩和苯并[ b ]噻吩的完全C3选择性芳基化。该转化的实用性通过显着的官能团耐受性和反应对H 2 O和空气的不敏感性得到证明。该方法也适用于含氮和氧的杂环,产生相应的C2芳基化产物。三相试验以及汞中毒和热过滤试验表明,催化活性物质在性质上是异质的。
Preparation of 1-phenylthio-1,3-dienes by reaction of 2,5-dihydrothiophenes with benzyne through fragmentation of sulfonium ylide intermediates
作者:Juzo Nakayama、Yuichi Kumano、Masamatsu Hoshino
DOI:10.1016/s0040-4039(01)80633-x
日期:1989.1
reaction of a series of 2,5-dihydrothiophenes with benzyne, generated from 2-carboxybenzenediazonium chloride, affords 1-phenylthio-1,3-dienes in good yields through the fragmentation of sulfoniumylideintermediates.