A New Route for the Synthesis of 3-Methoxythiophenes
摘要:
A new synthesis of 4-substituted, 5-substituted and 4,5-disubstituted 3-methoxythiophenes is reported. The reaction takes place in three steps in nealy quantitative yields starting from methyl 3-hydroxythiophene-2-carboxylates.
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
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。