Sustainable Manganese-Catalyzed Solvent-Free Synthesis of Pyrroles from 1,4-Diols and Primary Amines
作者:Jannik C. Borghs、Yury Lebedev、Magnus Rueping、Osama El-Sepelgy
DOI:10.1021/acs.orglett.8b03506
日期:2019.1.4
A general and selective metal-catalyzed conversion of biomass-derived primary diols and amines to the highly valuable 2,5-unsubstituted pyrroles has been developed. The reaction is catalyzed by a stable nonprecious manganese complex (1 mol %) in the absence of organic solvents whereby water and molecular hydrogen are the only side products. The manganese catalyst shows unprecedented selectivity, avoiding
In this study, common naturallyoccurring organic acids, namely oxalic, malonic, succinic, tartaric and citric acid (as safe, inexpensive, and biodegradable organocatalysts), have been employed for Paal–Knorr pyrrole synthesis. The organocatalyzed reaction proved to be effective in ethanol at 60 °C. However, the reaction rate is mainly dominated by the nature and position of functional groups on the
在这项研究中,常见的天然有机酸,即草酸、丙二酸、琥珀酸、酒石酸和柠檬酸(作为安全、廉价和可生物降解的有机催化剂)已被用于 Paal-Knorr 吡咯合成。证明有机催化反应在 60 °C 下在乙醇中是有效的。然而,反应速率主要取决于官能团在底物芳环上的性质和位置。这种无金属工艺可以容忍一系列官能团,应该被视为制药行业的一项资产,因为在吡咯支架的合成过程中不会发生金属污染。
Microwave-induced calcium(II) chloride-catalyzed Paal–Knorr pyrrole synthesis: a safe, expeditious, and sustainable protocol
alkaline-earth (Ca, Mg, Sr, Ba) chlorides, calcium(II) chloride was found to be a cost-effective Lewis acid catalyst for solvent-free synthesis of pyrroles from primary aromatic and aliphaticamines under open-vessel focused microwave irradiation. The salient features of this environmentally benign method are high to quantitative conversion, short reaction time, safe and clean reaction profile, possibility of
The synthesis of N-heteroaromatic compounds via an acceptorless dehydrogenative coupling process involving direct use of ammonia as the nitrogen source was explored. We report the synthesis of pyrazine derivatives from 1,2-diols and the synthesis of N-substituted pyrroles by a multicomponent dehydrogenative coupling of 1,4-diols and primary alcohols with ammonia. The acridine-based Ru-pincer complex
Herein, the first example of base‐metal‐catalyzed dehydrogenativecoupling of diols and amines to selectively form functionalized 1,2,5‐substituted pyrroles liberating water and hydrogen gas as the sole by‐products is presented. The reaction is catalyzed by pincer complexes of earth‐abundant cobalt.